Hyakugan Maoh's son. He's a centipede youkai so he can control centipedes, but he was also skilled at Yin-Yang and used Mahjong pieces as mediums to control shikigami. He was the youkai who was the catalyst for Hakkai's transformation into a youkai, and he lost his life once at Gonou's hands. Just as he was on the brink of death he buried a Mahjong piece in his own body, turning his corpse into a shikigami. He never saw eye-to-eye with his father Hyakugan Maoh, so they weren't close. He was overcome with the need for revenge at having his entire clan, as well as himself killed, and demonstrated an almost abnormal fixation on Hakkai in his psychological attacks on the man. He's like a sinister reptile with a clingy temperament. Incidentally, the things he had in his mouth like a cigarette are Mahjong counters. They can also be thrown like needles. The name Chin Yisou was one he gave himself after becoming a shikigami. It's the name of a Mahjong combination, as well as having the meaning "to be dyed in one color". Chin Yisou, or the single suit hand, is "All tiles in the hand are exclusively of one suit with no honor tiles". Chin Yisou controlled a huge crab-like shikigami as well, but impact-wise nothing can beat this creepy China-boy style puppet familiar. He cackles and spits seed beams from his mouth. It didn't come up in the manga, but his name is Ryuu Yisou. (Source: KonnyakuHonyaku LJ)
One of the five great Bodhisattvas who live in heaven, one who administers mercy and compassion. She, however, is a vulgar, boob-flashing, hermaphroditic, sexy Bodhisattva. This is the person who ordered the Sanzo Ikkou to go to the west. It may seem like she enjoys sending various trials at Sanzo and the others, but ever since 500 years ago she puts her heart and soul into watching over the way Goku and the others live their lives. In Gaiden, she displays enough natural power to knock out Goku after he'd changed into the Seiten Taisei. She might actually be the strongest. She is portrayed as a hermaphrodite in the manga, while in the anime it gives no indication of her being anything other than a female. In "Saiyuki Gaiden" she is Konzen's aunt, and the one responsible for bringing Goku to heaven. (Source: Saiyuki Wikia)
Sayuki (沙雪) is Mako's co-driver/navigator. Sayuki is a cheerful, outgoing girl and she is always looking for good looking guys like the Takahashi brothers. She also developed a crush on Takumi, finding him cute and invited him to a pool after his race against Mako and Sayuki. As navigator, she gives out instructions to Mako when they're racing (when to brake, what drifting technique to use etc.). Her last name is unknown. (Source: Initial D Wiki)
Genjyo Sanzo's master and the parent who raised him, this man is the previous Sanzo priest. He picked up the baby floating down the river, named him "Kouryuu" and brought him up. He was the protector of both the "Seiten Sutra" and the "Maten Sutra", but as soon as he entrusted it all to Genjyo Sanzo, he was attacked by youkai opposition and died. That life ended at 47 years. He is endlessly good-tempered and soft-mannered, but he moves at his own pace and is a natural fool. Even so, he shows a side so philosophical it is as though he can see far into the future. His is an old acquaintance of Goudai Sanzo, and together they spent their days as apprentice monks under the teachings of Arch-Bishop Jikaku. Koumyou succeeded to the "Seiten Sutra" and Goudai to the "Muten Sutra". Their friend, the youkai Tenkai Sanzo, walked the path of Sanzo priest with them, but with his death the "Maten Sutra" Tensan possessed was given to the care of Koumyou as well. Although this writing takes place 12 years after his death, Koumyou is a key person in "Saiyuki". (Source: Saiyuki Wikia)
Konzen Douji is Genjo Sanzo's previous incarnation. Kanzeon Bosatsu's nephew. His status as a god was high, but his job consisted mainly of paging through documents, and the boredom was killing him. He's a typical young master and doesn't know what hard work is; although he's the iron fist in a velvet glove and has a huge attitude, he has no strength or patience. He's pure only so far as he has no worldly knowledge. He met Goku, and was influenced by Tenpou and Kenren as well, and defeated his previous self in order to protect that which was important to him, gaining the determination to face up to a huge power. He has long, fine golden hair, and long-lashed drooping eyes. His appearance resembles Genjo Sanzo somehow. (Source: Saiyuki Wikia)
The Dragon King of the Western Ocean. Sole person responsible for Heaven's Western Army, Tenpou and Kenren's superior officer. He's strict about discipline as an army officer should be and undoubtedly takes heaven's orders as absolute. He discards excess things and is very punctual. He values Tenpou highly, and from early on, he rescued Goku and the others, who had begun to associate with Tenpou at some point, from danger. He got caught up in the fours' rebellion, and even though he didn't understand their thinking, he saw their paths with his own eyes. He has two horns growing from his silver hair. Scales dot his porcelain skin, and his eyes are red and gold. His strange appearance is closer to that of a youkai than a god. (Source: Saiyuki Wikia)
Nataku only appears in Saiyuki Gaiden and in the anime Saiyuki, episode called "War Prince Nataku". Nataku is based on the Taoist deity Nezha. He is a half-mortal war god who won the then-divine Goku's friendship. Unfortunately, Nataku falls into a catactonic state (the reasons for this are not disclosed in the anime) and sits in the divine garden of heaven with only the Goddess of Mercy to keep him company staring blankly ahead for all time. In the series, Nataku is decidedly more somber than Goku and is resigned to being a puppet (he was 'given the honor' of being the War prince, a role which is later passed onto Homura) to the Gods. Furthermore, Nataku goes by a different title, but his background is still very much the same - right down to a Commander father and spear weapon. (However, it is glaringly obvious as the series goes on that the Commander is exploiting his son for fame and recognition from the Gods, reversing the roles that Nataku is to blame for misfortune) Nataku's father however, is then lectured by Field Marshal Tenpou (the past reincarnation of Cho Hakkai) and further mistreatment of his son is then yet to be seen in the series.