As rich as he is, Sakyo enjoys gambling. However, he doesn't wager unless he knows the outcome, as he doesn't like to be surprised. He often wagers his own life on a match in order to gain the upper hand in a bet, and is a self-proclaimed egomaniac. Similar to Karasu in attitude, he is a calm and well mannered individual, never showing any signs of frustration or anger. The only notable time he showed shock was upon witnessing Younger Toguro's death, but even then he assumed his calmer, reserved persona just moments later. However, like Karasu, both of them are openly sadistic and cruel, enjoying the infliction of pain on various forms of life. He tortures his victims both physically and mentally, inevitably killing his targets.
While a vicious and despicable human being, Sakyo does possess a strong sense of honor and fair play, and murders anyone (like Butajiri rigging the favor on Team Masho) who uses cowardly and underhanded tactics to win wagers. Upon losing his final gamble (which he referred to as a "great bet") against Koenma, he graciously takes his own life as promised.
Sakyo grew up as the youngest of five children to a pair of poor, but loving parents, and is the only child amongst his brothers and sisters to not have ended up a "civil servant." In the original Japanese version, he seems to look back on his family life with a warm yet indifferent fondness ("My parents were decent and kind people; it was what you could call, an ideal family"). However, the English dub explicitly made him despise both his parents and the white-collar, conformist lives that his brothers and sisters lived, saying that he would kill himself if he ever found himself in such a situation. In both language versions, Sakyo never blamed his family for his transformation into a sociopath, but candidly admits that he is "rotten in the head" by birth.
Despite a normal adolescence, Sakyo was obsessed with death, violence and suffering; even going as far as getting an after-school job in a pet store in order to indulge his morbid appetite. He would occasionally challenge himself to see how long he could keep an animal alive after carving out it's heart. In the manga he also says he'd kill animals and insects out of boredom as well as dissect humans. Upon reaching adulthood, Sakyo discovered that he could translate his psychopathic tendencies into cold, hard cash by gambling. But he became addicted to the rush, caused by the knowledge that he could win or lose everything with his next bet, as well as the adulation that came with his wealth.
But even that got boring for Sakyo, so he started wagering his life for his prize fighter in order to get that same rush again. In the end, however, Sakyo's luck ran out. Honoring his bet after all, staying behind as the stadium for the finals of the Dark Tournament collapsed; taking him with it.
In the Anime version, he forms an exclusive relationship with Kuwabara's sister, Shiziru.