I Hate Systems - Chapter 992 The Ruler Of Deities

A teenager named Evan Mason was reincarnated into the magical world of Harry Potter and goes to school at Hogwarts!
With only his knowledge of the future and great talent for magic, he takes the path towards the top of the magic world, only to realize that ever step he took, changed everything!

- Description from Novelupdates

“Stop following me!” Asher yelled, his patience running thin. He had let it slide for too long because she had done a lot for him. But now she was everywhere, suffocating him.“I’m only trying to protect you,” she responded.Asher sighed, running a hand through his hair. “I need some space, alright? I can take care of myself.”She didn’t budge, and just kept staring at him with that same obsessive look, like she had no intention of leaving.“Is it because you’re strong now? Are you going to leave me because I'm no use to you anymore?” Her voice had turned cold, sharp enough to cut through the silence.“Of course not, you know that’s not the reason…”“Then why do you want me to stop following you?”“I’m just going to the restroom, for God’s sake!” He massaged his temple, clearly at his wit’s end.“Oh, you should have said that earlier.” She giggled, the earlier tension melting away.“I did,” he sighed in defeat.

The main character is reborn as a character from a game he played in his previous life. This character falls into ruin along with the villainess, spending the last of their years together. A man named Kururi Helan.

Blayn transmigrates into the world of Akame ga Kill and obtains the Mangekyō Sharingan—Kamui! Not just one, but both Kamui!