I looked at the stuff I liked, like corruption, netori, maledom, monster girls, and realized there are few games that scratch that itch. We have games with monster girls, like monster girl dreams, but they largely focus either on femdom or vanilla content.
The general idea is that you are a newborn demon (demons are not inheritably antagonistic in this world, more akin to fey) who belongs to a noble lineage. Except a war before your birth fucked up the whole world. So you awaken amidst ruins with nothing to your name.
You have a realm that can be heavily customized, similar to daedric prince realms from TES series. It plays like a mix of Castles from HOMM series and farms from stardew valley. This is your personal world and your base of operations.
Mortal worlds are split between people loyal to demons and those who fought against them. Potential targets can be both people eager to serve, like cultists, and people who want to kill you.
Due to lore reasons most corruption targets are virgins, and I eventually plan all central characters to be available in both monster girl and monster boy flavors (although they will share most content, only changing smut scenes).
No main quest, you are just left to your own devices. There are "ambitions", like becoming as powerful as possible, seducing a queen, creating your own race, becoming a patron deity of a race, etc. They are meant to provide a direction without chaining you to a single questline.
Fewer player races and transformations, but each with gameplay changing abilities which unlock new scenes and new ways to corrupt mortals. Since there is no combat you can treat these as classes which you can freely swap. Gain enough experience and you unlock that bodies parts and abilities for creating you own custom class/tf.
Sorry for writing a wall of text lol, I don't think this is a place for this kind of posts. Just ranting while I wait for godot 4.0 to release so that I can start migrating code from the previous version and fixing all the stuff that will inevitably break.