MTL - God of Life and Death - Chapter 3838 can't be better

A data loving young man from Earth has an accident which transports him to a dark land filled with terrifying creatures and magical powers. Fortunately for him, he has a Biological Assistance Chip to ease his path. However, things in this bizarre and strange world are not always as they seem, and, though it is a tremendous asset, the chip doesn’t always work as expected. With all of the crazy creatures and magical mayhem around him, one can only wonder what the future holds for this young man…

- Description from novelupdates

Xiao Chen, “the waste” of Xiao clan, had his engagement to the Young Lady of the Yang clan renounced.

And when he arrived at the sect that sympathized with him and took him in, he found corpses strewn all over the place and a mist of blood in the air. The sect was exterminated by a mysterious group that was looking for the ‘Wind Spirit Jade’.

He himself was left behind only half-dead for ‘wastes do not deserve to die by their hand’. Humiliated once more and on the verge of death, in the surroundings strangeness happened. A whirlpool sucked up the blood mist and diverted it into Xiao Chen’s forehead, transforming and enhancing his body.

- Description from Novelupdates

Then there’s James Bellini. His nickname? The Angel of Death.The man everyone fears. The man they all whisper about in dark corners. They say he’s merciless, that he has killed more people than anyone in the Circle. No one dares cross him. But there’s a secret, one that no one knows.James Bellini has never killed anyone. Not once.The rumors started because of a misunderstanding, a mistake so deep that even he couldn’t fix it. Now, the entire underworld fears him. Even the other bosses treat him like an equal, like he’s one of them. But the truth? The truth is something only God himself could untangle. And James? He’s just a man caught in the middle of it all.

You thought being reincarnated as an extra-side character was bad? Imagine being thrown into the body of a villain who is disowned by his own family and discarded by the author.