User blog comment:13SIlent/Monster Lord/@comment-24439699-20140214071148/@comment-4991168-20140214113309

It saysnso in the game. Alipheese tje 1st will return once a sufficient amount of monsters will be killed and their energy will be brought back into the flow of the world. Killing a monster = more dark eneelrgy returns to the flow. Same applies to angels. The logic is just a little different than what you were applying is all.

Even if it was not, Illias at the end of the game is a construct of light AND darkness so killing her affects both in similar amounts