I Fell into the Game with Instant Kill - Chapter 8.3: Asher Gronhilde (1)

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

mc gets transmigrated to Fallout New Vegas with the merchant system. let the questionable adventure begin.

Kuramoto Daisuke, a freshman in High School was suddenly exposed to someone vanishing in front of him. Turns out he was admitted to a Special Class full of Isekai Heroes that were regularly summoned to Otherworlds since the start of their Middle School. He was told that he was to become their Support to prevent each of the Heroes' fate of dying in the world they were summoned into. Though mediocre, he realized that his ability has a great potential but it needs a lot of hard work on his part.

Unconvinced of being just the Support Character, he vowed to excavate his mediocre ability, all the while supporting the Heroes using it.

And maybe more.

Betrayed. Exiled. Murdered. Reborn.In the war-torn land of Glory, power is everything and Duke Merlin's bastard son has none. Cast out to a starving border town beside the cursed Devil Forest, Kaelor and his mother were meant to die quietly.But when assassins take her life and leave him bleeding in the mud, another soul awakens within him one from another world.And with it, something else awakens too...The Fusion System.A power that lets him fuse nearly anything.Fusing one starving soldier with a dead direwolf gave birth to a Dreadwolf Trooper.Fusing one hundred wild dogs produced the monstrous Cerberus.Fusing two crumbling forts created a living fortress bristling with autonomous ballistas.From broken men and dead beasts, Kael will forge an army the world cannot understand and a dominion no one will dare challenge.