Substitute Marriage: Reborn As The Top Big-Shot - Chapter 122 - : 095: Use their own tactics to counter their own actions.

“If magic is power, then I'll build my own.” - Adrian.When a genius tech developer dies from overworking, he awakens in a world ruled by magic, ancient empires, and mythical beasts.But unlike the natives who manipulate elemental mana, he is granted a mysterious technology system that lets him reconstruct modern and futuristic tech.Armed with the knowledge of his old world and this game-like system, he begins to revolutionize the magic world. But his rise threatens the very foundation of society, drawing the attention of kings, mages, and forbidden powers that ought not to be offended.As nations clash and secrets unfold, one question remains:Can technology coexist with magic… or will one destroy the other?

Have you ever thought a monster that has a job of a summoner and a tamer

what should it call itself Monster Summoner? Monster Tamer? but he itself was a monster too

Watch as our mc travels the world as an reincarnated human who turn into a monster

Xia Yan passed through to the world of Bleach and became an eleven-year-old boy. He was rescued by Renji and Rukia in the Seireitei, and he was studying at Shin’ō Academy, and he was a student of the same class.
He is a top student of the Shin’ō Academy, and he is vying for strength by various teams. In the end, he has entered the first team of secret mobile maneuvers.
He will use punishment to kill every person who tries to threaten the martyrdom and protect his loved one.

- Description from Novelupdates

Tomokui Kanata has been reincarnated into the weakest race, goblin, and given a new name, Rou, after having undergone an unfortunate death. However goblin Rou has retained his previous life’s memories, an unusual evolution, as well as being blessed with ability to gain status boosts from eating.