Mage Legend - Chapter 67: Episode 14 Encounter_2

A dancer who was killed by a serial murderer found himself occupying the body and taking on the life of Brian Morse, a patient with anti-social personality disorder. As Brian, he has the look, he has the brain, he has the charisma, but he also has something that somehow always attracts psychopaths…[The story mentions 3 reality shows and crossovers with the American drama series Dexter. SLASH]

- Description from Novelupdates

“I’m a warrior from the alternate universe.”“The Goddess summoned me to this world to defeat the Devil that has imperiled the world and to restore peace to the world.”“I understand that it’s my cardinal duty. Since I’ve been summoned to become a Warrior, I’ll do my best to beat my opponent even if he’s the almighty Devil.”“Don’t ask me why. That’s what the book says.”“But… isn’t this development straying from the plot?!”This is the beginning of a scam in an alternate universe. It is also the story of a warrior with a mission to defeat the Devil. At the end, he realized that he had been duped instead.

After losing his parents to an accident, Haruto is thrust into a state of depression. Realizing he never had the power to change things, he eventually took his own life. Before moving on, he’s selected by beings greater than his understanding to balance out a world suddenly facing peril. The world of Mordell, where demon-like creatures and beasts roam, and Guilds of ability users called Warlords are the force to combat these creatures. Armed with the power to change things, he has the choice. Continue living in despair or accept his second chance and become a true Warlord.

Zavier met Cosmic Consciousness after his death. He was satisfied with every system that Cosmic Consciousness exhibited, so he wanted all of them. Surprisingly, the Cosmic Consciousness obliged him.

Zavier was reborn in an isekai full of magic and alchemy. Now, he had many routes to upgrade. Interestingly, to coordinate these systems, Cosmic Consciousness gave him the gift of being able to duplicate himself. He could clone a finite number of himself to manipulate these systems.

Magus, Alchemist, Mesmer, Tamer, Hunter, Vampire, Werewolf, Dragonknight, Necromancer.....

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By the way, it wouldn't appear NTR or some bullshit harem of courtships. MC of course will have harem but not for cliches.