Did you get the cut secene?
Once the Demon of Lies dies, the game will end and you'll witness the final cinematic sequence. The demon and the Sword of Lies are sucked into the abyss, but what happens with the baby? Do you kill it or carry it away from the dungeon? We'll have to wait for Divine Divinity 2 to find out.
If you did not get the cinematic sequence then I do not know what happened. If you saved before the battle you may need to try again.
Or maybe Raze or Lynn has a better answer for you.
Good Luck and good gamin
J.W.
