DxD: Building A Demon Clan From Scratch. - Chapter 12: Supernatural Investigation Club

I was reincarnated into another world, and I’ve brought the Horadric Cube from Diablo II with me.
Being a knight is cool and all, but being a wizard is pretty neat as well.
So, which one will it be?

- Description from Novelupdates

The protagonist is an accidental time traveler - he didn't wait, didn't guess, only dreamed, but ended up in history, which he didn't pay much attention to. He was just lucky with his lineage.Ryo is a new member of the Nara clan, from the Uzumaki lineage on his father's side, and it so happened that he was born not at the beginning of the known plot, but more than three decades and two world wars later. Now he has to figure out how to get out of this situation however he can.

I transmigrated into a novel that I was reading.“But of all people, why did it have to be Kamon Vade?!”The problem here is this: the character I transmigrated as was a third-rate villain who appeared at the beginning of the original story, but after he had been accused of attacking the imperial princess, he disappeared and left the stage.“Haah, fine. The novel never said that I died anyway. So, I just need to somehow hold out and endure in the academy, right?”But…Maybe because I refused to exit the novel, ‘death’ keeps following me around.‘Motherfxxxer, this is like the fantasy novel version of Final Destination!’Damn it, I have to survive somehow.And I will! No matter what!

When I transmigrated, the protagonist was already dead.Now, I have to protect the world after the bad ending.So first things first, I became the enemy of the main heroine, who was on the brink of ending her life.“I finally understand what all those things you said really meant.”“I’m like this because of you, junior. Take responsibility.”“I can only sleep when I’m next to you.”…But for some reason, everyone is starting to act a little strange.