Casino Kid is a living sinner brought back from the dead through a broken reincarnation machine. He is a physical soul that still holds many of his abilities.
He is obsessed with poker, to the point that it's practically his only personality trait. As a soul, his body reflects this: poker chips for eyes, a pompadour in the shape of a spade, a black, white, and red suit with a blue cape, the only thing that doesn't fit this pattern is the red X on his lower torso (assumably a death mark from liver failure).
His signature ability is to pull people that try to attack him into a pocket realm. In this realm, if they choose to play, they bet their senses in a game of poker. If they can no longer bet another sense, they go braindead. If they cheat, he will make them go braindead.
In the pocket realm, physical damage is disabled so he can't be hurt. The only way to even prick his finger… is by playing poker with him, and he first died at around the time poker came into existence.