Industrial Cthulhu: Starting as an Island Lord - Chapter 125: Are You Competing with Monica in Innovation?

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

streak of being publicly humiliated in every story route. In other words, he was the designated cuck of the game Academy of Roses.Too bad for everyone, Cassius is now possessed by Arawn—a burned-out gamer who just tried to kill himself after exacting savage revenge on his sister’s cheating husband.Waking up in the body of the most pitiful character in eroge history? Not ideal. Finding out his missing sister has also been isekai’d and is now pretending to be Cassius’s noble “sister” to avoid suspicion? Wild. Realizing she’s about to be married off in another forced engagement plot? Yeah, fuck no.Armed with system powers(everyone has it), broken stats(for your average joe), and a big 'sister complex'(Not Incest) on steroids, Arawn has one simple plan: Live a peaceful life with his sister, for it he would, Break the rules. Shatter the narrative. And if anyone tries to play the protagonist? Use them for his own plans.This time, the cuck’s got teeth. And he bites back—in the most painful ways.—————Warning: The MC is a villainous character, he is psychotic, manipulating, borderline insane and unhinged. So, please keep that in mind

The eldest son of the assassin aristocrat Tuatha Dé.

The skill, experience, knowledge of the previous life, magic, all of which grows his power as an assassin.

Excellent assassins pass through. He was usually admired as the ideal lord, and behind it wielded a blade as an assassin aristocrat.