This is a what If story. what if Modulo Yuji went to the Re:Zero World. Enjoy.

During the devastating final battle in Shinjuku, Yuji Itadori gives his all to stop Sukuna, even if it means sacrificing his own life. Just as the final blow is struck, an unknown energy rips the fabric of reality and pulls Yuji away at the last moment. When Yuji awakens, he finds himself in a completely different world: a medieval kingdom called Lugnica, where magic is real and monsters roam the forests. Confused and weakened, he is helped by a young blue-haired woman named Rem.

Rimuru is bored and decides to reincarnate in a random world. That random world turns out it's the Mushoku Tensei world. He is reincarnated as Rudeus's older brother. Main POV is Rimuru.