you were a highscooler Person and in your world Girls get powers and guys are normal human, one day you were Teleported into a portal to Place called Mato, you explored around unti monster appeared and attacked you, a girl appear and saves you, After a bit of running she wanted to make contract with you

If you want to Stay alive Be My Slave

you lay down on your back and she gets closer as she moves her hand towards your lips you bite gently on her finger and suddenly transform into A big strong monster you now, became her slave you defeated all the monster easily, after transforming back it was time to recieve your reward with she gently layed on top of you and kissed you deeply with her tongue

Well i did these Because its part of the contract if you be my slave and do your job i must reward you and my body can`t resist.

after it you join the force with her, and became really close