Blaster Tempest Cleric Build - Thunder Apostle - Baldur's Gate 3 (BG3)

Blaster Tempest Cleric Build - Thunder Apostle

The build at its core is a full-fledged cleric. The Tempest Domain comes with additional lightning and Thunder-themed spells offering a solid start for a strong caster. However, to further empower this setup, I recommend multiclassing into Sorcerer, allowing to create destruction on turn 1.

The build will cover a few main aspects, the first being a Cleric and this opens support spells like Healing Word, Mass Healing Word​ together with The Whispering Promise. The combo will prove valuable in early and mid-game.

The second aspect is being a controller able to weaken foes with various status effects. This is where Spirit Guardians​ and various items like Boots of Stormy Clamour and Gloves of Belligerent Skies come in. Moreover, thanks to a few other items most of your offensive spells will also apply Reverbation and Radiant Orbs.

However, the most important part comes from the Sorcerer and being able to access Metamagic: Quickened Spell. You can cover the whole battlefield in water using Create Water​ and then follow up with a full spell like Call Lightning​ + Destructive Wrath​ for maximum damage.

Using Haste​ or Potion of Speed with Bloodlust Elixir will allow you to continue using Call Lightning​ without expending more spell slots. So you can cast a 3 times level 6 lightning spell with maximum damage. After this lightning rush, not many enemies will be able to stand up.

So let's get into the build

Class Contribution

The build mostly goes into Cleric to obtain all the core parts of the Tempest Domain. Sorcerer comes into play to empower the caster parts of the build.

9 Tempest Cleric

• Access to healing and support spells - Mass Healing Word​ and Healing Word​
• Can apply wet status for other casters with Create or Destroy Water, to empower your Lightning spells.
• Spirit Guardians​ - the ultimate cleric spell, to debuff enemies, making them miss their attacks. To make the most out of it you will need some gear.
• Tempest Domain offers Destructive Wrath, allowing you to deal the maximum possible damage with your spells.
• Access to various reactions and spells related to the Lightning and Thunder theme - Wrath of the Storm, Call Lightning, Sleet Storm, Destructive Wave.
• Proficiencies with shields and medium armor, allowing to improve defensive capabilities further.
• Your lightning and thunder spell effects can push foes away with the Thunderbolt Strike​ effect. It can easily result in an instant kill if enemies are close to the ledge.

3 Sorcerer

• Provides Constitution Saving Throw proficiency which will help maintain spell concentration.
• Access to Shield, which is an excellent cheap survivability boost if the situation demands it. The +5 Armour Class is a huge boon, allowing you to avoid deadly attacks.
• Access to a variety of cantrips like Friends, which are especially useful if you are the main character, as you can win over some of the dialogues with low charisma.
• Unique Storm Sorcerer feature - Tempestuous Magic, giving a huge boost in mobility.
• Metamagic mechanic and Sorcery points. You will be able to cast full spells using Metamagic: Quickened Spell, giving a unique advantage over normal cleric builds.

Leveling Overview

Here is a concise table with all the main picks during your leveling progression. For more detailed reasoning, I go further in the article. Also, do not forget to check the recommended gear as it is crucial.

Level	Class	Selection
1	Cleric 1	STR - 8, DEX - 16, CON - 15, INT - 8, WIS - 17, CHA - 8
		Skills: any
		Cantrips: Sacred Flame, Produce Flame, Guidance​
		Prepared Spells: Guiding Bolt, Command, Inflict Wounds, Sanctuary, Healing Word​
		Subclass: Tempest Domain
2	Cleric 2	-
3	Cleric 3	Prepared Spells: Lesser Restoration, Enhance Ability, Hold Person, Spiritual Weapon​
		Cantrip: Thaumaturgy​
4	Cleric 4	Feat: Ability Improvement - +1 Wisdom +1 Constitution or +2 Wisdom
5	Cleric 5	Prepared Spells: Spirit Guardians, Glyph of Warding, Mass Healing Word​
6	Sorcerer 1 (respec as first level)	Cantrips: Friends, Minor Illusion, Blade Ward, Mage Hand.
		Spells: Shield, Magic Missile​
		Subclass: Storm Sorcery
7	Sorcerer 2	Spells: any utility spell
		Metamagic: Metamagic: Extended Spell​, Metamagic: Twinned Spell​
8	Sorcerer 3	Spells: Mirror Image​
		Metamagic: Metamagic: Quickened Spell​
9	Cleric 6	-
10	Cleric 7	-
11	Cleric 8	Feat: War Caster: Concentration​ or Alert​
12	Cleric 9	Prepared Spells: Insect Plague​

Starting the Game - Level 1

This section covers the creation screen and what would go into the best Races, Abilities, and Skills for the Blaster Cleric build. Some of these choices are impactful as you cannot respec them.

Races

Picking a race provides various benefits - abilities, dialogue options, looks, etc.

Race	Features	Description
Wood Half-Elf	Civil Militia Darkvision​ Fey Ancestry Fleet of Foot - your movement speed is increased by 1.5m.	The race picks are very similar, the main difference is weapon proficiencies. However, the cleric subclass will already provide everything that you need. The most important aspect is the increased movement speed that you will need when using Spirit Guardians.
Wood Elf	Elven Weapon Training​ Darkvision​ Fey Ancestry Fleet of Foot - your movement speed is increased by 1.5m.
High Half-Elf	Civil Militia Darkvision​ Fey Ancestry	The High subraces of elves can be useful as they give access to cantrips like Friends, which are especially good for the main character.
High Elf	Elven Weapon Training​ Darkvision​ Fey Ancestry
Halfling	Halfling Luck Brave	The good thing is that Tempest Domain does not need to be as much on the frontlines and can play as a caster. This opens up options for shorter races.
Blue Dragonborn	Lightning Breath​ Draconic Ancestry​	Although the race is somewhat disappointing, it still fits the theme pretty well, as it represents lightning elements.
Bronze Dragonborn	Lightning Breath​ Draconic Ancestry​

Class

Overview
Cleric
Clerics are representatives of the gods they worship, wielding potent divine magic for good or ill.
Features
Spell Slots	These can be used to cast spells and are restored each long rest.
Domain Spells​	Unique spell list accessible based on your cleric subclass.

Cantrips

Cantrips	Description
Sacred Flame​	The main damage cantrip of clerics deals radiant damage. Early in the game, it is underwhelming, due to low Spell Save DC, but later it can be a decent option when you are saving spell slots.
Produce Flame​	It can be used to light the area around you, but also deals 1d8 fire damage. This is a recommended general damage option early in the game
Guidance​	The most important cleric cantrip, which improves various ability rolls, works on yourself and party members.

Subclass

Overview
Tempest Domain
Features
Wrath of the Storm​	Especially early in the game, this gives an excellent use for reaction.
Thunderwave​	A decent spell that can be used to throw off enemies from ledges.
Fog Cloud​	Cover an area in fog, which can be used for pickpocketing or making combat easier.

Deity

I would suggest Talos, as it represents thunder and lightning.

Prepare Spells

Clerics get plenty of good level-1 spells. You might not have enough slots to equip them all but don't worry, more will be available as you level up. Choose your preferred ones.

Spells	Description
Guiding Bolt​	The main, long-range damage spell for the cleric in the early game.
Create or Destroy Water​	The core spell of this build will allow your Lightning-based spells to deal double damage. In most cases, you will be able to destroy simple grunt foes.
Inflict Wounds​	If enemies are close to you, this is the go-to spell, which a strong damage rolls. It can also crit, inflicting even more damage.
Command​	One of the best control spells in the game, if you have a high chance of landing it. What makes it special is that it does not use a concentration slot.
Sanctuary​	Use this spell to make the ally untouchable, for example, if they have low HP, or you want to divert the enemy's attention.
Healing Word​	The best healing spell, due to its cheap cost and ability to revive downed targets without wasting action points. Moreover, later with The Whispering Promise ring you can buff specific allies.
Bless​	This is an excellent spell, however, I would only use it before combat and in the early game. It loses value later on, especially with some excellent items you can get in Act 1 like The Whispering Promise.
Shield of Faith​	Excellent early game spell, that can be used to improve defensive capabilities. I would not use it too much at higher levels as you get better use for concentration slots.

Background

Backgrounds are mostly for role-playing and you can pick whatever you prefer. If you want to optimize, then it would be good to pick backgrounds that are based on your ability points of Wisdom.

Abilities

Now let's take a look at the abilities of the Tempest Cleric build. Correct allocation will allow you to maximize the early gameplay and get good modifier bonuses.

Ability	Value	Description
Strength	8	Not relevant for the build
Dexterity	16 (15+1)	The key ability of the build will give increased damage, initiative, and armor class.
Constitution	15	The constitution will play a major role in maintaining spell concentration and HP pool. If you will be getting Auntie Ethel's Hair, set this to 14, and put 2 points elsewhere.
Intelligence	8	Least important stat for the build.
Wisdom	17(15+2)	The main spellcasting ability for clerics. This should be maximized to have success with spells.
Charisma	8	If you set Constitution to 14, you can allocate 2 points here.

Skills and Expertise

Overall, the skills should be impacted by your roleplaying and background decisions. However, you would still want those that will give you the best benefits. My recommendation would be to go for these, most relevant to the theme of the build:

• Animal Handling
• Insight
• Medicine
• Perception
• Survival

Leveling Progression - Levels 2-12

Here is the detailed progression for the Tempest Cleric to get you started. You can use it as a guideline because early games can be daunting and overwhelming. Later on, once you get a feel for the class you can start picking your options

Level 2

This is where you will have left the tutorial area, and will start exploring the world. 

Action	Description
Turn Undead​	Excellent against undead enemies, making them run away.
Destructive Wrath​	The main feature of Tempest Domain allows it to deal maximum damage with Thunder and Lightning spells.

Level 3

At this level the Cleric gets access to Level 2 spells, further expanding the spellbook. Moreover, new always-ready spells are introduced.

Spells	Description
Gust of Wind​	Can be used to push back foes.
Shatter​	Excellent spell to deal with Scrying Eyes that you will encounter in some places. Shatter​ should destroy them instantly.

Prepared Spells

Spells	Description
Lesser Restoration​	I recommend being aware that you have this spell, as there are situations where it might be useful. It does not have to be always in the prepared spell list.
Warding Bond​	Excellent spell, that you can use to greatly improve the survivability of one of your party members.
Hold Person​	Can be situationally useful, especially if you have an 80%+ chance to land it. It can also shine if you start using the Scorching Ray​ + Hat of Fire Acuity combo.
Spiritual Weapon​	Gives a good use for bonus action. The weapon deals okay damage and can act as a distraction.
Enhance Ability​	Almost a mandatory spell to have by someone in the group. This can help with various ability checks and turn the tables to your side.

Level 4

Level 4 brings the first feat, it will be a huge improvement.

Cantrips

Cantrip	Description
Light​	This cantrip will be useful together with the Coruscation Ring or Callous Glow Ring to enable their effects.

Feat

Here you can select from a few choices, based on your playstyle and what kind of playthrough you are doing.

Level 5

This level is a huge milestone, and that is why no multiclassing happened before. Access to level 3 spells, provide a big step up in terms of damage and enemy debuffs.

Feature	Description
Destroy Undead​	When you use Turn Undead, you will also deal bonus radiant damage. I think this is a good addition, but nothing fancy as it has niche uses.

The Tempest Domain subclass also gains special spells:

Spell	Description
Call Lightning​	This is spell slot efficient spell, especially if you plan on having a longer encounter. For example, in the late game, you can cast it as a level 5 spell, and continue recast it without expending more slots. Add Create Water​ on top, and you will deal double damage.
Sleet Storm​	Extremely powerful control spell that is usually overlooked, because it does not have any damage. However, you can make enemies prone with it, cancel the concentration of spells, and cover an area in ice. After this, enemies will have to pass Dexterity checks to not get prone and skip their turns.

Prepared Spells

Now, this is probably the most important section as you will gain some game-changing spells, allowing you to win many encounters.

Spell	Description
Spirit Guardians​	This is one of the strongest cleric spells, that will be your bread and butter throughout the game. It will be used to weaken enemies using the Radiating Orb status effect.
Remove Curse​	This can be useful throughout the game in case you or a party member gets cursed.
Glyph of Warding​	You can use this Glyph to apply various damage types and effects. For example - fire, cold, lightning, etc. The main highlight is Sleep, which works on multiple enemies and can outright win you an encounter.
Mass Healing Word​	Using this as a bonus action together with The Whispering Promise will buff all allies with the Bless​ effect.

Level 6 - respec to Sorcerer Lv 1

Now, to further empower Cleric and its capabilities you will have to respec and pick Sorcerer as a first class:

• Get proficiency in Constitution Saving Throws. This is important as it allows you to sustain Concentration on spells while being hit.
• Access to defensive spells like Shield.
• Have the correct spellcasting modifier on items, which depends on the last class taken via multiclassing (it will be Cleric).
• Access to metamagic, specifically for Metamagic: Quickened Spell​ to enable casting with your bonus action.

Class

Overview
Sorcerer
Features
Spell Slots	These can be used to cast spells and are restored each long rest.

Cantrips

Take those cantrips that do not rely on damage as they will be using the Charisma modifier, which will be low for Druid.

Cantrip	Description
Friends​	If you are the main character and do most of the dialogues, this is also a good choice as it gives an advantage during rolls.
Blade Ward​	Can be useful in some situations, where an ally might be in a pinch, and you have no good use for action otherwise.
Minor Illusion​	You can use this cantrip to pull enemies together before an encounter.
Mage Hand​	Can be used to solve some puzzles and overcome obstacles.

Spells

Spells	Description
Shield​	Very good spell that can ensure +5 Armour Class giving a good survivability boost.
Magic Missile​	I recommend this spell. It is not very powerful, but it can be used to specifically hit a foe, with multiple attacks and using Callous Glow Ring apply a lot of Radiating Orbs to weaken its hit chance.

Subclass

Overview
Storm Sorcery
Features
Tempestuous Magic​	After you cast a Level 1 spell or higher you can Fly as a bonus action until the end of your turn without receiving Opportunity Attacks.

Abilities

Reuse the same ones from the 1st level.

Level 7 - Sorcerer Lv 2

This is more of a progression level, giving a glimpse of one of the main mechanics that will be fully utilized after the next level.

Actions	Description
Create Sorcery Points​	Spend Spell Slots to gain Sorcery Points. Once you get some more metamagic options, you could sacrifice spell slots, to cast two spells in one turn or increase your range
Create Spell Slot​	Spend Sorcery Points to unlock a Spell Slot. You could create a higher tier spell slot, to increase the damage over what you can at the current level

Spells

Because your spellcasting modifier is Wisdom, you should go with any utility spell like Enhance Leap, False Life, etc.

Metamagic

To be fair, none of these matter, as the goal is level 3 options.

Metamagic	Description
Metamagic: Twinned Spell​	Can be used to twin some of the spells, overall Cleric does not have many of these.
Metamagic: Extended Spell​	Increases the duration of spells. I would mostly recommend using it on Command, making it last 2 turns.

Level 8 - Sorcerer Lv 3

You can now pick level 2 spells and additional metamagic options.

Spells

You can only choose two options. I would recommend something that is not offensive and does not rely on a spellcasting modifier:

Spells	Description
Misty Step​	Can be used to move around the battlefield. The main drawback is that this effect is similar to Tempestuous Magic, albeit better.
Mirror Image​	Can have niche uses when you are standing in the front.

Metamagic

Metamagic	Description
Metamagic: Quickened Spell​	This is the goal of Sorcerer Multiclass. You will be able to cast full spells using your bonus action. With correct preparation on some turns, you can unleash deadly storms with all your lightning and thunder spells.

Level 9 - Cleric Lv 6

A new subclass feature is unlocked. Moreover, you can select one more feat.

Feature	Description
Thunderbolt Strike​	With this feature, you will be able to see some silly situations, where enemies are pummeled around from your spells. It does not provide too many practical bonuses and sometimes can even have negative effects, of spreading enemies apart.

Level 10 - Cleric Lv 7

Level 4 spells are unlocked, also new permanent spells are added:

Spells	Description
Ice Storm​	An excellent spell that has a few good uses. First, it can cover an area with Ice. Second, each of the hits will apply a separate instance of Radiant damage with Callous Glow Ring, and Coruscation Ring will apply 4 stacks of Radiating Orbs, greatly weakening foes.
Freedom of Movement​	Has some niche uses, when you would want an ally to freely move on difficult terrains. However, the spell slot cost is quite steep.

Prepared Spells

Sadly, there is nothing much to recommend. The spells can be situationally good. However, none of them will change the core rotations of Tempest Cleric.

Level 11 - Cleric Lv 8

A new subclass feature is unlocked. Moreover, you can select one more feat.

Feature	Description
Divine Strike: Thunder​	The only time this would be used is when I would activate Attack of Opportunity, otherwise it does not serve much purpose.

Feat

Feat	Description
War Caster: Concentration​	This will help maintain spell concentration while being hit. Some items give the same effect, but these will most likely go to other characters.
Dual Wielder​	I would only pick this in rare situations where the Cleric is the only cater in the group. This way you can use all the cool staves from Act 3.
Alert​	If you constantly want to go first and avoid any surprise rounds, this feat guarantees that.
Ability Improvement	Getting +2 Wisdom, especially if you are Shadowheart will alleviate the low Wisdom values due to no access to Mirror of Loss.

Level 12 - Cleric Lv 9

Level 9 gives access to level 5 spells

Spell	Description
Insect Plague​	Area control spells, that can impose difficult terrain and apply a decent amount of damage on targets walking through it.
Destructive Wave​	Excellent spell, that can also make foes prone, making them easy targets for your allies.

Prepare Spells

Spell	Description
Greater Restoration​	Removes negative status effects, that can be useful in some situations.
Flame Strike​	Deadly spell that creates a pillar of fire dealing both fire and radiant damage.

Maximizing Ability Scores

Now, as the build progression is covered there are a few aspects and important decisions you will have to make throughout the game. These will decide your final score for abilities.

1. Act 1 - Auntie Ethel Hair - you will want to get +1 Wisdom if you pick this choice.
2. Feat - Ability Improvement - +2 Wisdom
3. Act 3 - Mirror of Loss - pick +2 Wisdom.

This will allow you to reach 22 natural Wisdom. This is the maximum value. Without Auntie Ethel Hair, you will maximize it at 20.

Potions, Elixirs and Consumables

Let's take a look at what consumables you can use to further empower the build.

Potions

These are general consumables, and most of them are activated for a few turns. Potions are separate from Elixirs and can be active together.

Consumable	Description
Potion of Speed	In case you or your other casters have a Concentration spell slot taken and cannot cast Haste, use this potion. It acts similarly, but the effect is just for 3 turns.
Potion of Animal Speaking	Although not something powerful, it is worth stocking up and saving a spell slot.
Potion of Invisibility	Can be used to get a perfect position before the encounter starts.

Elixirs

Unfortunately, only one Elixir can be active at a time. However, the good thing is that they last until a long rest, making them very useful and economical.

Be sure to activate them before combat as otherwise, you will need to use Bonus Action.

Consumable	Description
Elixir of Bloodlust	Very effective elixir that gives another action point if you kill an enemy. I would say this is the best one to use to maximize your output through the turn.
Elixir of Battlemage's Power	Gain 3 stacks of Arcane Acuity. I would say this should be the most used elixir for higher spell success.
Elixir of Peerless Focus	Another good choice that allows to better maintain spell Concentration.
Superior Elixir of Arcane Cultivation	Grant's a single level 3 spell slot. Could be useful in case you are preparing for a longer encounter.
Supreme Elixir of Arcane Cultivation	Grant's a single level 4 spell slot. Could be useful in case you are preparing for a longer encounter.
Elixir of Vigilance	For some encounters, you will want to go first. This elixir will ensure that it overcomes even surprise mechanics. However, if you have Alert​ this becomes redundant.

Illithid Powers

This special mechanic in Baldur's Gate 3 allows you to consume tadpoles and unlock special Illithid Powers.

At first, you can only use the base powers. As you move to Act 3, you will be able to unlock the outer ring powers.

Illithid Power	Type	Description
Favourable Beginnings	Base	Beneficial power to take as it does not have any costs, and provides only benefits on the first hits.
Luck of the Far Realms​	Base	Guarantees a critical hit, use it on important targets, that you want to make sure are killed. This works well with spells like Inflict Wounds​ which have attack rolls.
Psionic Overload​	Base	As this is Psychic damage, you will double it to 2d4 thanks to Resonance Stone.
Psionic Backlash	Base	A decent use for reaction to deal some bonus psychic damage.
Cull the Weak​	Base	Can help to kill an enemy faster if it is left with a few HP.
Illithid Expertise​	Elite	As you are not a charisma-based character, these proficiencies help with dialogue checks.
Black Hole​	Elite	One of the most powerful illithid powers. You can use it to pull enemies together. If you can follow up with Call Lightning​ + Destructive Wrath, the combo will destroy most of the enemies.
Psionic Dominance​	Elite	Can be used to save yourself from a deadly spell. This is especially relevant as you will have a disadvantage on mental saving throws.
Freecast​	Elite	Remove the cost of spell slots or charges.
Mind Sanctuary​	Elite	You can now use action and bonus action interchangeably, giving two full spell casts each turn.

Equipment Recommendations

Now I would like to go through some gear recommendations to maximize the Blaster Tempest Cleric Build. Items are especially important as they take the build to the next level thanks to their unique effects.

Act 1

The core items of the build are obtained in Act 1, so be sure not to miss those items as they will play a crucial role in making the Lightbearer effective.

Slot	Item	Description
Melee (One-Handed)	Defender Flail	If you do not care about the unique effects, this is a go-to choice. The bonus Armour Class will help you avoid enemy hits and activate Holy Lance Helm.
	Blood of Lathander	I think this weapon deserves an honorable mention. It looks cool and has satisfying and useful effects.
	Phalar Aluve	This is one of the best weapons in the game for a supporting class like Cleric. If you can precast its Phalar Aluve: Melody before combat, I recommend using it both to improve companion damage or attack rolls.
Ranged	Bow of Awareness	Gives bonus initiative, allowing one to go earlier in combat.
Shield	Adamantine Shield	It provides a substantial defensive boost by reducing critical hit damage.
	Safeguard Shield	Gives a bonus to saving throws, easily accessible early in the game.
Head	Holy Lance Helm	A solid helmet that will deal 1d4 radiant damage if the enemy misses you. Moreover, it will also activate any reverbation effects from Gloves of Belligerent Skies.
	Haste Helm	Improves movement speed, allowing one to reach important targets easily, early in the game.
Cloak	-	Nothing relevant for the build
Armor	Luminous Armour	This is the best armor for the whole game.
Gloves	Gloves of Belligerent Skies	One of the best gloves for builds that apply status effects via various damage sources. This will create Reverbation, increasing the chance of making the enemy Prone.
Boots	Boots of Stormy Clamour	The best boots in terms of offensive damage. They will give Reverbation stacks when you apply status effects, for example, Spirit Guardians.
	Disintegrating Night Walkers	One of the best boots, giving a total advantage for movement on difficult surfaces. It also gives Misty Step​ to increase that mobility.
	Boots of Speed	Excellent boots that improve movement capabilities, especially useful when you are running around with Spirit Guardians​ active.
Amulet	Amulet of Restoration	The best cleric amulet early in the game. Use the spells together with The Whispering Promise to apply buffs on your allies.
Rings	The Whispering Promise	The best ring for a cleric early in the game. This will apply Bless​ to allies when you use the Mass Healing Word.
	Crusher's Ring	Excellent ring that will allow you to move around more. This is especially useful before you obtain Tempestuous Magic​ from Sorcerer dip.
	Ring of Protection	The bonus Armour Class is a great boost for survivability.

Act 2 - mid-game

Slot	Item	Description
Melee (One-Handed)	-	Sadly, Act 2 doesn't have any caster weapons that would help specifically this build, so continue using the ones from Act 1.
Ranged	Bow of Awareness	In my opinion this still plays a major role, especially in a few encounters in Act 2.
	Hellfire Hand Crossbow	Equipping two of these will allow you to shoot using off-hand and activate Divine Strike: Thunder.
	Hand Crossbow +1
Shield	Ketheric's Shield	The best shield for casters as it gives +1 Spell Save DC, increasing spell success.
	Sentinel Shield	What makes this shield amazing is that by wearing it you will be going first most of the time during encounters. This is a great way to apply Radiating Orb and Reverbation on enemies using Spirit Guardians.
Head	Fistbreaker Helm	Adds +1 Spell Save DC improving spell success.
	Hat of Storm Scion's Power	This helmet can be useful to improve your Spell Save DC a little. Still, your thunder spells like Shatter​ even if hit by multiple enemies will only give 1 stack.
Cloak	Thunderskin Cloak	Because most of the enemies you come across will have Reverbation this cloak will further help to weaken those foes.
	Cloak of Protection	Improves survivability and Saving Throw success. You want to equip this cloak to maintain that good Armour Class.
Armor	Luminous Armour	The best armor for clerics using Radiant damage.
Gloves	Gloves of Belligerent Skies	Continues to be the best glove option due to the easy way of applying Reverbation from various damage elements.
	Luminous Gloves	Alternative option, that will add 2 more Radiating Orb stacks as you inflict damage.
Boots	Boots of Stormy Clamour	Still the best boots in terms of applying various conditions.
Amulet	Amulet of the Harpers	Allows casting a Shield​ spell, and can be a lifesaver if attacked heavily for one turn.
Rings	Callous Glow Ring	The ring's bonus radiant damage will help activate Gloves of Belligerent Skies and get more Reverbation stacks.
	Coruscation Ring	This will help with building Radiating Orb stacks. However, with all the effects you will be applying, this might be overkill as you will already be proccing Luminous Armour.
	Ring of Mental Inhibition	Excellent ring that can be used to apply Mental Fatigue from failed Saving Throws against your spells.
	Ring of Spiteful Thunder	Adds another Dazed effect that can be procced after 5 Reverbation stacks are activated and Thunder damage gets applied.

Act 3 - Final Build setup

Act 3 is where the build will get the best items, to maximize its effectiveness and damage.

Slot	Item	Description
Melee (One-Handed)	Markoheshkir	I understand that this staff has minimal chance of being used with Tempest Cleric. However, it has an excellent synergy via Kereska's Favour, allowing it to activate Bolts of Doom. This unlocks Chain Lightning, which can deal huge damage with your Destructive Wrath.
	Staff of Spell Power	Another staff for casters comes with the Arcane Battery​ feature, giving a free cast without spell slot cost.
Ranged	Hellrider Longbow	The bonus initiative is an excellent boost to go early in combat. If it is not a surprise round, it is almost guaranteed.
	Hand Crossbow +2	This is an improved version that you can dual wield with another hand crossbow, for an offensive option using bonus action.
Shield	Viconia's Walking Fortress	One of the best shields in the game. Overall, it serves more of a defensive role giving advantages on Spell Saving Throws.
	Ketheric's Shield	The best shield for casters as it gives +1 Spell Save DC, increasing spell success.
Head	Hood of the Weave	One of the best headwear for spellcasters, giving +2 Spell Save DC. This can be contested by other casters as it is in high demand.
Cloak	Cloak of The Weave	Improves Spell Save DC. However, the main caveat is that this cloak is in demand by all casters.
	Cloak of Displacement	Provides an increased chance of avoiding enemy attacks with attack rolls.
Armor	Luminous Armour	Still the best armor in the game.
Gloves	-	Reuse the same gloves from previous acts.
Boots	-	Reuse the same boots from previous acts.
Amulet	Amulet of The Devout	Overall, the best amulet for Cleric builds. Gives additional Channel Divinity Charge and improved Spell Save DC.
Rings	Ring of Feywild Sparks	Reuse the same rings from previous Acts.
	Callous Glow Ring	The ring's bonus radiant damage will help activate Gloves of Belligerent Skies and get more Reverbation stacks.

Build Mechanics

In this section, I would like to dive deep into how to play the Blater Tempest Cleric Build. This will help you utilize it to the fullest and correctly use various actions and spells throughout the game.

Important Mechanics and Combos

Let's go through key mechanics and tips on how to use the build effectively.

Healing and Buffs

The main misunderstanding about clerics is that people assume they should only be healing and supporting. However, this is far from the truth. In general, the best healing mechanic is just throwing potions, which is efficient, and cheap in comparison.

Overall, healing should be limited and in my opinion, used sparingly. My recommended spells are Healing Word​ and Mass Healing Word. These are cheap to use and cost only bonus action, which does not interfere with your important spells that will be covered later.

However, the major highlight is that those healing spells activate The Whispering Promise ring buffing your allies. This is very valuable early in the game, so that your party has a higher hit chance, making combat easier.

Otherwise, I would leave any other healing spells for out-of-combat.

Spirit Guardians - Cleric's bread and butter

So the most important spell for Cleric is Spirit Guardians. With the correct gear that I recommend each enemy you touch, will apply various status effects like Reverbation, Prone, and Radiating Orb.

So you are like a running Beyblade damaging everything that you touch and also weakening their combat potential. Just remember the core items to make this work - Luminous Armour, Boots of Stormy Clamour, and Gloves of Belligerent Skies. There are some other options, but overall these are the best picks.

So the idea is to run around and have as many as possible enemies touched by your light. However, this might be limiting in some cases, where enemies might be on higher ground or behind covers. This is where the next step comes in...

Tempestuous Flight

Taking a level 1 dip into Sorcerer unlocked one of the features that will greatly improve Light cleric mobility - Tempestuous Magic. This will allow you to fly at the cost of bonus action, not use movement speed, and avoid opportunity attacks.

While flying any enemies you touch with Spirit Guardians, will be affected by it. This is an excellent way to spread Radiating Orbs and debuff most enemies in the combat zone.

Sorcery points and Metamagic

One drawback of this build is that to use Metamagic: Quickened Spell​ you will need Sorcery points. With 3 levels of Sorcerer, this will result in 3 points, which allows only one use. However, this can be overcome by using Create Sorcery Points.

This action can consume spell slots, and level 2 ones are perfect as these spells don't offer anything overpowered. So if you consume 3 level 2 spell slots, you can use Metamagic: Quickened Spell​ 3 times per long rest, which is not bad, considering you can do that once per short rest (if having Bard).

Easy way to apply wet

If you are in a bind and want to save Action Point without casting Create Water, there is a cheaper alternative. You can throw Water Bottle from the inventory onto the ground or close to the enemies.

The next step will require some kind of Hand Crossbow +1 so that you can shoot with offhand. Now hit the bottle with your arrow, and it will break, applying wet to the nearby targets.

Maximum Lightning Damage

The main highlight of Tempest Domain is what they access at level 2 - Destructive Wrath. This allows dealing maximum damage with Lightning spells. Now imagine, you use Call Lightning, upcast it to level 6, apply Wet on enemies, and activate Destructive Wrath. This will result in 120 damage per target.

If you will have Haste​ and Elixir of Bloodlust + Metamagic: Quickened Spell​ you can cast the same spell 3 times. This is 360 damage just on a single target, and many times a few of them will be standing together.

Another thing to consider for the Thunder Apostle build is to equip Markoheshkir and use Chain Lightning​ - the numbers become even more ridiculous.

Reverbation and status effects

The main highlight of any Cleric build is the sheer amount of status effects you will apply - Reverbation, Prone, Radiating Orb, Daze, etc. This can greatly weaken foes and make them harmless to your group.

The main highlight in my opinion is Reverbation. This at first weakens enemy strength, dexterity, and constitution saving throw proficiencies. As it stacks to 5, the enemy will get damaged with 1d4 thunder. This is finished by making the enemy prone if they fail a saving throw.

Once the enemy is prone they are easy pickings for your melee characters and waste their precious movement speed to stand up. To get these effects consistently be sure to use Boots of Stormy Clamour and Gloves of Belligerent Skies.

Early Game Combat

Let's cover how you should progress combat levels 1-6. You will be limited by the amount of spell slots you have.

• For early encounters use normal spells like Guiding Bolt and, Inflict Wounds. To save spell slots I would prioritize Produce Flame​ followed by Sacred Flame​ to inflict damage
• If you can use Bless​ to buff allies before combat. Once you get The Whispering Promise, you can forgo the spell and use Healing Word​ or Mass Healing Word​ to buff your allies.
• Once you obtain Spirit Guardians​ use these to run around the battlefield and debuff the enemies. Check the equipment section for the items that work the best with it. This should be your main spell for the time being.
• Create or Destroy Water​ is an excellent spell if you have other casters that use Cold or Lightning spells.
• Your bonus action has plenty of uses. The already mentioned healing spells, but you can also summon Spiritual Weapon, which can deal additional damage and distract foes.
• Glyph of Warding​ can be used to put enemies to sleep without a Concentration slot. It is excellent if you see a few of them grouped up.
• If things are turning for the worse, you can always use Sanctuary​ to save an ally or use it to flee combat.

Late Game Combat

For the late game, there are a few things to consider, but overall you will fall into one of two combat options, depending on the required results:

Nova Round

This should be used when you want to evaporate your foes and win the encounter as fast as possible.

• Be ready to chug Potion of Speed or obtain Haste. You can also drink Elixir of Bloodlust as it will give another action point.
• Apply wet on enemies using the Create or Destroy Water​ or Water Bottle trick that I mentioned.
• Unleash your spells - Call Lightning​ with the highest level spell slot. Follow up with recasts, and finish with Metamagic: Quickened Spell. This can result in 3 casts, which should evaporate most of the enemies.
• If you have Markoheshkir, use Chain Lightning. Just it alone can tear through a group of enemies.
• Destructive Wave​ is another option, as it will proc multiple status effects from your items like Luminous Armour, Callous Glow Ring, etc. damaging and weakening enemies. The spell also has a huge area of effect, that other lightning spells don't have.

Normal Round

I recommend this option when you are worried about spell slots and want to conserve them. This option will use lower-tier ones, saving the higher ones, for bigger encounters:

• If you see the upcoming encounter, precasting Create Water​ can be useful for other casters. Otherwise don't worry about it.
• Spirit Guardians​ is your starting spell. After that reach enemies close to you so that they get damaged and debuffed. Tempestuous Magic​ will allow you to fly into a group of enemies or avoid risky Attacks of Opportunity.
• On the next turn, you can use Sacred Flame​, Guiding Bolt, and Inflict Wounds​ for some decent and cheap damage sources on the next turns. The spells will also activate Tempestuous Magic​ so you could again damage foes with Spirit Guardians.
• You can also start combat with something like Sleet Storm, especially on melee enemies, as they will get prone, waste their movement speed, and may slip on the ice again. Ice Storm​ can do the same effect, but it will use a Level 4 spell slot.

Build Variations

I don't think the build has many worthwhile variations. You can go with pure Cleric for the third feat, but overall this does not change much, with the build being already very powerful.

Conclusion

Thank you for reading the Blaster Tempest Cleric build - Thunder Apostle for Baldur's Gate 3. This caster build can unleash a fiery storm on Nova round and end any kind of encounter with Thunder at it's fingertips. If you want something aggressive with Cleric, this build is for you!

Cheers!