Sacrifice Yourself, Then Eat Me

He, who may have been reincarnated as an indescribable being, meets a Japanese high school girl who died by suicide. From then on, he blends into human society in her identity...

This is the tale of a newborn Cthulhu girl causing the whole world's SAN levels to plummet as she stirs up trouble.

"So, boy, do you want to become stronger?"

"Then offer up your soul, and then, eat~ me~ up~" | ^o^y-~~

P.S. Since no one can have an intimate♂ conversation with an indescribable being, I guess the protagonist will just have to stay single.