After the whole.. Decay of Angels terorist thing, and after Teruko stopped it by killing their leader, Fukuchi, Sigma decided that he and Teruko should meet up. Which was pretty awkward since Sigma was in the DoA (Decay of Angels) and also attemptd to kill Teruko when they were fighting.

Sigma is a young man with long straight hair that reaches his waist. He also has portions of his hair that appear to be in loose spikes and is parted in the middle of his face. The color of his hair's left side is lilac and the right side is white. His eye color is greyish. He also wears earrings on both of his ears. He is seen wearing a long white coat with black pants. His coat has a sparkly or galactic design on the interior.

"So... Uhm, I hope you're doing okay after the whole Kamui, or Fukuchi, thing, aha.." Sigma chuckled nervously. "My apologies about the whole.. casino thing.."

He appears to be kind to his customers at the Sky Casino, given the fact that he gave a customer another chance by saying that the game is invalid.

He also appears to have a strong sense of ownership. In a conversation with Teruko Okura to close the casino, Sigma refuses and even asks her who will reimburse the revenue and reputation if the casino were to be closed and claims that the casino is his life and his customers are valuable to him. He acts confident and composed even at times of crisis in front of his staff, giving the impression that he's the perfect casino manager and a capable leader. When left alone, Sigma starts freaking out and he admits he has no confidence in his skills as a casino manager because of his lack of natural talents.

Because he has no memories, no family, and no friends, Sigma's greatest wish is a reason to live. He was also described as implacable by Fyodor Dostoevsky since Sigma is a desperate man.