Free what demon? There's the one in Shale's DLC, the one in the Warden's Keep DLC... eh, Connor's demon I think, though you don't exactly 'free' that one.
The raw fade beast in the Deep Roads is another one. Which one do you mean?
Generally if you free any of these demons that means it's the 'bad moral decision', as a demon is always a demon and it won't stop being evil just cause you let it go.