Obtaining Corpse Explosion for Eithne The trader - Divinity: Orignal Sin 2
The skilbook is needed to finish the quest Eithne the Trader. An undead will want to die and a solution is this skill. To obtain the skillbook is fairly easy. Use crafting menu and combine non-source necromancer and pyrokinetic skillbooks.
You can find her in Cloisterwood. The precise location with coordinates: X162 and Y222
For selling her the book you will gain 13450 experience for each of your party members