Marvel: The Ultimate Superman - Chapter 3. Perfecting the Super Soldier Serum

The hero who was killed by the demon king ended up reincarnated as the son of the one who killed him! Thus began the life of the hero who donned in the mask of the ideal demon prince to topple his own kingdom while doing his best to prevent anyone from discovering his identity―― But to do that and blend into the demon tribe society, he had to kill his former comrades. Nevertheless, to become stronger, to save humanity, he had to walk through all kinds of paths of carnage! This is the tale of the demon race’s fake prince destroying his own kingdom.

O Hero, Trample Those Who You Should Protect!

TN: Most part of the other character in the novel is depicted from a non-human perspective so expect something that is completely different from the common sense of human.

SLASH!(So this is death?!!)I, Elysia, found myself dead before even reaching the Demon King's lair, and our Hero Party was completely annihilated.And this was done by none other than a fellow human—my former classmate.He had been mostly invisible during our time at the academy, but then he started committing one crime after another until he became a lackey of the Demon King.Who would have thought that the strongest party of humanity would be wiped out by humanity’s traitors?(If I could go back to the past, I swear I will kill you!)Just when I thought I could finally pass on, I opened my eyes.Five years back, when I first enrolled at Arcadia Academy.And there he was, the traitorous bastard of humanity...****“Huh? Where am I?”One day, I opened my eyes to find myself in an unfamiliar place and came to realize this was the world within the novel Savior's Dawn that I had read.Everything seemed to be proceeding the same as in the novel—except for one thing.The main heroine is glaring at me as though she wants to kill me.Could I survive with the main heroine after my life?

She shouldn’t have got drunk, so she wouldn’t have court the troubles.
She slept with a handsome man and would be sent to the police?
Oh, my sweet Jesus…
“So you just ran away like nothing happened after you slept with me?”
“Old jerk! Even if I had the initiative, it was you who took advantage of me!”
As a saying goes, the more spoiled a president gets, the more likely he becomes a scumbag.
An adorable ‘wildcat’ vs. a scheming frenemy.
This was a love rivalry between a modern Cinderella and a Big Boss.
As time flew, the world was like a fleeting show.
When they met again after several years of separation, he held her hand tightly and swore that he would never give her any chance to leave him again!
Finally, he asked her to marry him and pampered his cute wifey with his endless love.

- Description from Novelupdates

The story of a returnee who lived in the world of martial arts for 20 years and plays games instead of hunting monsters.Summary:[TS] Martial Arts Returnee’s Game Broadcast follows a martial artist who, after returning to modern society and undergoing a gender transformation, becomes a game streamer. The story mixes martial arts with gaming and live-streaming elements in a contemporary fantasy setting.