As Aizen in Naruto and Joined a Chat Group - Chapter 261: Vampire Count

Ace had always harbored feelings for his childhood friend, only to have his heart shattered when he learned she was secretly in love with Duke. The betrayal left him disheartened, but nothing could have prepared him for what came next.That night, instead of waking up to another ordinary day, he opened his eyes in a completely different world—inside another man's body. Worse still, the first thing he heard upon waking was yet another rejection.Thrown into an unfamiliar land with a past he doesn't remember and a future he never planned for, Ace faces a choice: chase after love once more or embrace a new passion—one that comes in the form of an unexpected farming system. As he cultivates spirit crops and reaps rewards beyond imagination, he begins to wonder: perhaps love isn't found in a person, but in the soil, the growth, and the endless possibilities of the land.Will Ace sow the seeds of a new destiny, or will the echoes of rejection root him in the past?

After dying in laboratory tests, Klaus transmigrated to a Sorcerer World, in a strange and peculiar character whose existence is an enigma. He knew this world, for it was the world of the novel one of his students wrote. He also knew the character because he created it. But it was a discarded character; it never appeared in the novel. How could he have transmigrated in it? Reality hit him soon after when he was sent to cross through the first test that every sorcerer must pass to awaken his abilities. There, he will have to fight against powerful monsters, which they call Curses, and against other Sorcerers, all to try to enter the select group of Sorcerers to discover the secrets that await in this world and understand his arrival to this and his existence. Just when he thought his journey might be boring, he received a peculiar and mighty power bordering divinity, capable of making him reach unimaginable heights. Although a bit dangerous...

The well-known and recognized throughout the Stern continent, strong and mighty, as well as the unique Wizard of magic cures, the most outstanding genius of the whole continent, Jason got into the flow of time, back in the uncivilized era during the first failed experiment, 3000 years ago. This was the period when the magic healers didn’t exist. How will Jason apply his knowledge in this backward era, wherever he reach the peak of glory?

- Description from Novelupdates

There are a total of seven sins, and a revelation is made to a young man named Alex that he is destined to become a demon lord, more especially a demon lord of sin called LUST.

It's not like he can change that and because he always knew something about himself was different—not in a physical sense, well, maybe a little—and not in a mental sense—but rather because he is thrown into a demonic war that compels him to accept his new reality.

He was only aware of a difference in himself. Relating to him and the ladies who are drawn to him... Well, it was more or less like he was a magnet in front of all the girls, and all the girls were drawn to him like a metal.