[@Sikako J]
Shin is my Oldest and Boldest character. He's had the most work put into him over the years, and he's the character I'm most familiar with.

Shin was born in Alternate Universe Number Who Gives a Damn, this is not the same universe as LeeRoy's origin universe of Universe Number Who Fucking Cares. LeeRoy was born in Who Fucking Cares and wound up in Who Gives a Damn, this is how they are connected. 

In U#WGaD, society is much different. It's industrial age a few years early. In the 1700s. Pretty much everything was the same, except political ideals started way earlier. I was going to go into super deep detail about it, but I'll just summarize.

Young Kid: Normal but apathetic child, no demonstration of psychopathic tendencies.
Teenager: Trained in Martial Arts to give him a strong foundation.
Young Adult: Joined a society known for killing people, but far above the law. He killed his first man and found out his nearly sexual obsession with death.
Adult: Became obsessed with becoming physically perfect so he can kill more efficiently, it becomes like a drug addiction at this point.
Middle Age: Shin was sent out to kill a man who was reportedly Immortal. LeeRoy. 

Unfortunately, this is how he gets his facial scar. Shin breaks into LeeRoy's laboratory as he's working on his Thermal Gauntlets, winds up catching a facefull of burning hand. Obliterating his eye and ruining his face. Then he was thrown from a third story window, just before he hit the ground he was selected as a potential Godslave. 

The God of Form saw his obsession with physical perfection as a perfect medium for him to enslave Shin. Shin was granted immortality and The Black Staff. 

He then spent the next few centuries perfecting his body.

Edit: 
[b]FACT:[/b] No matter who Shin fights, no matter who they are as a person. They suddenly become the most emotionally stolid and immovable individual. Losing all emotional ties to their sense of self.

It's funny how that coincidentally ignores his jeering and vulgar manner of speech.

Total coincidence though.