A BA x Kamen Rider fanfiction, an extended Kamen Rider story based on Kiwotos.

The story begins with the erosion rain half a year ago. An abnormal phenomenon called pollution begins to appear in Kivotos. The polluted place is called pollutant, and the pollutant will generate strange people called corrosive bodies.

The protagonist is Xia Lai's teacher, who transforms into Kamen Rider AIM by chance.

(This is my first time writing a fanfiction, please don’t blame me if it’s not good)

ooc and other issues can be pointed out

The Silent Bookstore, a library perched on a small island in Cornwall, houses countless secret teachings and profound techniques. After a devastating fire, the entire bookstore was deserted and sealed off until a new librarian took office on a stormy day. Uesugi Sumi, a reincarnated individual, not only found himself in a world pieced together from numerous anime series, but also became a survivor of a shipwreck brought by the storm in another world. He successfully took over the Silent Bookstore, inheriting the library's resources and knowledge. To repair his bookstore, he decided to cultivate his own "tools" to make it easier to get freebies. Yotsuya Miko: He's a good person, though sometimes he doesn't seem quite human. Hikigaya Hachiman: A good person, but not entirely good; at least sometimes he doesn't seem like a good person to his friends. Goto Ichiri: A terrifying person, but very kind. Faced with these assessments, Uesugi Sumi, a master of nine arts, a master of initiation, a master of medicine, and an all-around worker, said, "Let's make friends... and get me a room while you're at it."