Seirei Gensouki – Konna Sekai de Deaeta Kimi ni

Amakawa Haruto is a young man

who died before reuniting with his childhood friend

who disappeared five years ago.

Rio is a boy living in the slums

who wants revenge for his mother

who was murdered in front of him when he was five years old.
Earth and another world. Two people

with completely different backgrounds and values.

For some reason, the memories and personality of Haruto

who should’ve died is resurrected in Rio's body. As the two are confused over their memories and personalities fusing together, Rio (Haruto) decides to live in this new world.
Along with Haruto's memories, Rio awakens an unknown "special power," and it seems that if he uses it well, he can live a better life. But before that, Rio encountered a kidnapping that turns out to involve two princesses of the Bertram Kingdom that he lives in.
After saving the princesses, Rio is given a scholarship to the Royal Academy, a school for the rich and powerful. Being a poor orphan in a school full of nobles turns out to be an extremely detestable place to stay at.