Kamen Rider: Earth's Heroes And Rider Taisen!

[Kamen Rider x Reverse Isekai My Hero Academia Crossover!]

Years after Kamen Rider Ichigo and Nigo defeat Shocker every time. The Shocker give up to defeat Kamen Rider and give up to destroy the Kamen Riders. They research the multiverse and find a world doesn't have Kamen Riders, they don't need a lot of Monsters so they will start from over and decide to merged two worlds into one because Kamen Rider defeat them.

A young man who is a huge fan of golden age era Kamen Rider who wear a toy mask that he stop the a group of gangsters harrassing innocent people. He was kidnapped by Shocker and convert him into a cyborg, then Takeshi Hongo help him to escape. And he learn the world of MHA is merged with his world into one. He will learn how to be a Kamen Rider to protect his world!