Sakyo was the owner of Team Toguro, and the youngest, most eccentric member of the demon smuggling criminal syndicate known as the Black Black Club.
He is voiced by Nobuyuki Furuta,and in Japanese and by Eric Vale in the FUNimation English dub. He is called Mr. Valdez in the Filipino dub of the anime.
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 an indifferent yet strangely warm 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 disect humans. Upon reaching adulthood, Sakyo discovered that he could translate his sociopathic 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. However, rather than losing everything, he became so good at gambling that he acquired enough wealth to join the Black Black Club, a criminal organization consisting of perhaps the most wealthy men on the planet.
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.
Spirit Detective Saga
Along with the other members of the Black Black Club, Sakyo makes his first appearance on a large television screen, at Tarukane's mansion. As Yusuke Urameshi and Kazuma Kuwabara make their forceful way through the hordes of demons, who where guarding the mansion, Sakyo wagers his entire fortune on the boys's successful defeat of the Toguro Brothers. However, this was all just an elaborate ruse, orchestrated by Sakyo and Younger Toguro, who faked his death at the hands of Kuwabara.
After Yukina was rescued by Yusuke and Kuwabara, and the other BBC members had stopped their transmissions to the mansion, Sakyo reappears on screen, ordering Toguro to kill Tarukane, who fell into insanity after realizing that he had just lost his entire wealth on Toguro's loss. Afterwards, Sakyo agrees to Toguro's wish of having Yusuke and his gang participate in the Dark Tournament.
Dark Tournament Saga
In the early stages of the tournament, Sakyo watches from a VIP area about the ring, conversing with either the other members of the Black Black Club or Toguro.
When Shizuru angers Keiko and storms out of the arena, Sakyo saves her from a league of demons who were prepared to rip her apart. Before leaving, he tells her that here, they are the minority, and that she should be careful from now on. The day before the finals, Sakyo was approached by the tournament committee who asked him about his intentions. He revealed that he planned on opening a tunnel to Demon World, big enough so that even the most powerful demons could enter the Human World at their leisure . He explains that in doing so, he hopes to bear witness to all of the destructive powers that demons would amass, without them being restricted by Spirit World's laws. The committee was shocked and thus ordered for Sakyo's death. However, Toguro arrives just in time, and kills the entire committee and their demon assassins. Toguro is then asked if he, by any chance, disapproved with Sakyo's plan. Toguro states that he was more than happy with his intentions, for it was the only way he could keep on fighting more and more powerful opponents. Afterwards, Sakyo made a toast with Toguro, in honor of their success.
Just before the final match between Toguro and Yusuke is set to begin, Sakyo publicly makes a deal with Koenma; the owner of the losing team would die in order to ensure that one of the teams would win. Koenma agrees to the wager, shocking the audience, as well as Team Urameshi in the process.
Halfway through the final match, Toguro begins devouring the souls of the audience, amplifying his already formidable strength in order to defeat Yusuke, who at the time had the upper hand. As the people try to run as far away as possible from the fight, Sakyo activates a giant wall around the stadium, trapping every single person and demon inside. He then states that their lives are worth less than the tickets they had purchased in order to see the finals and that only the winners of the tournament will walk away alive.
After Toguro had finally lost, Sakyo uses a self-destruct protocol on the stadium in order to reduce it to rubble, killing himself in the process. Before he is crushed by the rubble, he has a brief conversation with Koenma. Then he hands over a rather special lighter of his to Shizuru, who was upset that Sakyo had to throw away his life so easily.