Calypso

Calypso was born into a huge underground experimental facility where scientists would conduct strange experiments on various animals. As a newborn kit, the scientists injected him with a strange concoction of chemicals and who knows what else, this completely corrupted his DNA (showing in the unnatural blue spots and bands) and destroyed his immune system as well as other health issues. Because of his near non existent immune system, he had to be contained in a special room where no other animals or humans could interact with him, basically solitary confinement, and his air water and food had to be absolutely pure and clean. As you could imagine, this was extremely expensive to maintain for long and soon the facility had to shut it down. Many test subjects were relocated into his room, all of them horribly scarred, sick and sometimes mutated. Almost instantly, Calypso caught one of their sicknesses and was said to die within days at most but... he never did. It turns out the injections the scientists gave him as a kit made him practically immortal, but this was not a good thing. Calypso was in constant pain and always weak due to always being sick. Over many many years, his immune system did strengthen slightly and he was no longer constantly bed ridden, he could walk around and even run for a short time on a good day but he was still terribly weak. Taking advantage of this, the scientists began a new test on him: Effects of physical pain caused by emotions. They strapped him in a shock collar that was hooked up to his brain, and when the sensor implanted in his brain received signals it would send a signal of its own to the collar unleashing a shock onto Calypso's body. 

Other tidbits?

- Left (his right) eye is ALWAYS squinty because he was born with tight skin around the eye.

- Black goop/mucus around eyes is ?? from a past/present disease

- ?? Eh?