I'm trying to get into this game, but being a fan of light-hearted things like Monster Girl Encyclopedia makes it really hard. I do however have a suggestion. The player-character is supposed to be some kind of warrior of the in-game goddess who is meant to fight the succubi, right? Well, Why not give him the option once he reaches a certain combat potential (level) to drain a succubus of all her power using the goddesses power once he defeats her and revert her to the form of a human.
Like this, you could neutralize the threat without killing her and also have sex with her without dying. Just a food-for-thought idea, if you wanted to think about it.
Hi!
-This game is supposed to be darker. It was made out of my disappointment on how most media portraits the succubus as cute little things instead of a dark demonic entity that their original source/legend/myth dictates.
-My succubus are
demons like the ones in the bible, they are inherently corrupted (even if not necessarily evil) and seek domination over lesser beings to serve as food for them, since they are the ultimate parasites.
-They see you as nothing more than food.
-Succubus are spirits formed in hell, not humans.
-Although a succubus can be female mortals corrupted by an Incubus. He can turn them into lesser succubus without clan (but they are barely recognized by the "pure succubus"/hierarchy as a succubus at all.
-I developed a lot on the succubus in Succubus Covenant. Being a succubus is way more then just power. When a mortal is corrupted she expels from her body all her natural organs (except the brain) leaving only enough to form another one, a succubus stomach, that can process sperm as energy from them to sustain themselves. The original succubus only have these to begin with. Therefor you can't "absorb their power".
-There is no true "gods" here, only this endless battle between angels and demons and humanity in between.