Solasta: Crown of the Magister

This achievement occurs after you beat Razan in the Fortress of the Shield during the main story. Razan gets away, and for this achievement you need to find and kill him. Exit the area all the way outside to those 2 pillar projection puzzles you had to do to get in. You'll see the quest marker nearby if you're tracking it. If you're facing the entrance of the fortress, go right and interact with the coffin for the fight. I was playing on easy so I can't offer many tips. There will be another enemy like Razan and 3 of those Brood of Blood zombies or whatever they are. Razan will get extra turns like last time as well. I started the fight with a Fireball and then moped them up from there, you can hit 4 of the 5 enemies with it if you get initiative and can move before they do.