Uruha Kurenai is composed of its captain, Kurei, and four other members of the Jyushinshuu.
Kurei was the leader of Uruha Kurenai. Kurei controls the black flame and even though he does not possess powerful flame dragons, he can still prove to anyone that he's worth becoming the flame master.
Kurei uses his flame in the form of a lamenting lady named Kurenai. "Kurenai" is actually the name of the girl he loved whom his father, Kōran Mori, killed. When she is destroyed, Kurei can effortlessly create another one. It also turns out that Kurei has already learned how to summon the so-called holy flame—a phoenix.
Joker is a mysterious man who wields the Taishaku Kaiten. In his dealings with the Hokage, he primarily dropps hints about their opponents and their own powers while keeping them in the dark regarding his true intent and nature. It is only during the final round of the Ura Butō Satsujin that the Hokage Team finds out that Joker is part of the Uruha Jyūshinshu, and is a member of Uruha Kurenai. He initially gets involved with the Uruha through attempting to fight Jisho, one of the members of the Jyūshinshu, and saying that he intended to kill all the members of the Uruha. He fights Jisho continuously for two days, and then meets Kurei only to reveal that he wanted to join the Uruha in the first place. Kurei then offers him a spot in the Jyūshinshu, and Joker joins on two conditions: that he can live the way he wants and can leave whenever he wants to, and for him to be allowed to be informal since it 'pains him to be respectful'. He is also known for having a Kansai accent.
Noroi wields the madōgu Bakuju, which actually has a mind of its own and eradicates a human's memories and consciousness in order to possess his/her body. When the body he currently possesses starts weakening, the Bakuju looks for a younger, stronger body to be its new host. After Noroi is overpowered by Domon Ishijima, the Bakuju tries to possess Domon, but his strong will overcomes Bakuju's power.
Mikoto uses a number of madōgu throughout the series: the three large puppet madōgu (Mikoto, Shirahige, and Ōtobide), Dokumashin and the Gedokugan. She's noted to be cruel and ruthless, or a 'female version of Mokuren'. In the manga, she has a romantic relationship with Mokuren. She later appears in both the Sealed Lands and SODOM City arcs.
Kai wields the weapon Hyōma En, which can manipulate ice and is the evil counterpart of Tokiya Mikagami's Ensui. In the manga, the Hyōma En has a mind of its own and constantly demands to be fed blood. Kai studied Hyōmon Ken under Meguri Kyōza, who also trained Mikagami. Through constantly comparing him to his senpai Mikagami by saying that Mikagami is "gold" and he is "stone", Meguri Kyōza instilled within Kai a sense of anger and revenge in order to show Mikagami how futile living his life only for revenge is. Kai battles against Mikagami in the final round of the tournament and manages to defeat him, fulfilling his desire to be the best Hyōmon Ken master and in order to avenge his broken pride. After telling Mikagami not to live a life of revenge the way he himself did and that it was Meguri Kyōza who killed Mifuyu, Kai stabs himself with the Hyōma En to feed its thirst and allows himself to fall into the pit below the arena. In the anime, Kai is supposedly the first Hyōmon Ken successor, but is discarded soon after Meguri Kyōza noticed Mikagami's potential. He also says that Meguri Kyōza killed Mifuyu, but adds that Meguri Kyōza's reason for doing so is because he believed that revenge would drive Mikagami to train harder (he says nothing about Meguri Kyōza's motives in the manga). After his battle with Mikagami, he does not stab himself with the Hyōma En, but he still allows himself to fall into the pit. Kurei shows respect for him by telling Mikoto not to speak ill of him after his victory/death.