Monstergirl Maker

How it Works: The user places his hand on a willing subject and asks three questions - what they want the most, how they want to get it, and what they’re willing to give up for it. If the subject answers truthfully, they, over a 1-minute period, painlessly transform into something both female and not human (though they might still be able to pass for human) in such a way that either their wish is granted, or they can grant their own wish.

Limitations: Neither the user nor the subject has any control over what kind of Monstergirl the subject turns into. Furthermore, an unhappy subject may turn hostile immediately upon completion of the process.

Variants:

-Demon Lord: Now, your Monstergirls will become grateful regardless of the result of the process, as well as becoming loyal to you. This loyalty is not unbreakable, so treat them well, or you may find trouble brewing in paradise…

-Contagious: Your Monstergirls can turn other humans into the same kind of Monstergirl. This is completely optional on the writer’s part, so just taking this doesn’t mean their Holstaur Waifu has to be able to do this just because their Vampire Waifu can.

-Suck-You-Bus: Your Monstergirls must consume vital essence from humans in order to live. What form this vital essence takes is entirely up to you (blood, semen, life energy if you want your Sailor Moon fix, etc.), but all of your Monstergirls must do so. They do not have to consume the same kind of vital essence.

-Ritual: Rather than the user having this power themselves, it can be done by anybody who performs a 15-minute ritual. The user still has perfect knowledge of how to do so.

-Eldritch Waifus: Your Monstergirls are ‘off’ somehow. Perhaps they don’t look like anything remotely recognizable, or their forms come with off-putting instincts that you/they need to manage. Whether you still find them attractive is up to you.

-Skip the Questionnaire: Forget the quiz, you can just turn people into Monstergirls straight away.

-Incognito: Your Monstergirls have a human form that they can adopt to blend in. This may or may not be the same as their original human form.

-Monsterboys: You want your Husbandos? Here’s your Husbandos.

-Fit Right In: Nobody’s concerned about your Waifus being inhuman beings. Why should they? From their perspective, it’s always been that way.

-Remote Control: You no longer have to touch the subject, just engage them in conversation.