During the first series The Nightmare Begins, the first guest comes across Roulette Boy's gameroom and is warned by Gregory to vacate before he shows up. Too late, Roulette Boy pulls both the guest and Gregory into his board game-esque challenge, resulting in Gregory getting blown up twice, crushed by a massive weight and then dropped into a pit at the finish. He approaches the guest to spin him again but the guest wisely leaves.
In The Last Train, he briefly transforms the entire train into a massive board game challenge with Gregory once again being the victim. This time, obstacles such as a rolling boulder and large flood ravage the train and Gregory.
Firstly, the player character must find Roulette Boy's dice in a game room in the basement levels of Gregory House. After doing so, the player character must find Roulette Boy and accept his "Hell's Roulette" challenge with Gregory as the opponent. The player character must make it to the last space and win the game in order to achieve the soul.
That said, Roulette Boy becomes hostile afterwards and will damage the player character via Horror Show.
Roulette Boy's Horror Show involves the player character being forced to spin him. The player character tends to be unlucky and gets flattened by a massive weight like those in the "Hell's Roulette" game.
Roulette Boy is a kid first and foremost who loves games to the point of perpetually drooling in anticipation of the next one. He takes great pleasure in forcing people to undertake his games of chance and watching victims be harmed by the effects of their bad luck (usually the massive weight). He also is something of a showman given the extravagant spotlighting and crowd noises applied to the board game seen in Soul Collector and The Last Train.