He is the younger brother of Tendou Koutatsu, the leader of the Sokai Faction, an extremist faction of the Jouishishi. Two years prior, the gang was hidden in the Rokkaku Hotel, extorting the manager Rokkaku Muneharu to help them. They planned to start fires all over Edo as a diversion while they assassinated the Shogun, but in the last minute, the Shinsengumi found out about the plans of the faction, and invaded the Hotel, resulting in thirty six violent deaths between the Sokai and the Shinsengumi, amongst them, Rokkaku Kirie's father and the manager of the Hotel, as well as Tendou Koutatsu, Soutatsu's brother. The Sokai was supposedly eradicated during the incident, while the Shinsengumi suffered only three deaths out of the five First-Division Officers they sent. The three survivors of the incident were Okita Sougo, Kamiyama and Tendou Soutatsu, who was hiding during the incident. From his hiding spot, he could see Sougo and Kamiyama planning to lie about Rokkaku Muneharu's death, blaming the Jouishishi to cover the fact that he was killed by the Shinsengumi. In the years to come, he went on to try and revive the Sokai faction to one day use his knowledge about the death of Muneharu to get revenge on Sougo for killing his brother and the rest of the Faction.
He has a rather feminine look, with long blonde hair, bright red lips, probably due to lipstick and reddish red eyes. He is seen wearing a pink colored kimono with flower patterns and a vibrant purple fur scarf, as well as red earrings.
He is very manipulative, as well as egoistic, using even little girls to do his bidding as he pleases. At first he seems like a cold and meticulous leader to the Sokai Faction, acting with arrogance when everything is according to plan, but once he notices that he no longer has the advantage, he quickly gets taken over by fear, and starts to cry, scream and run away from danger.
Strength & Abilities
Sword Skills: He carries a sword, but uses it mostly for threatening others. Since he was hiding during the Rokkaku Accident and runs in fear when his subordinates are defeated by the Yorozuya and the Shinsengumi, it is safe to assume he isn't very good with fights.
Charismatic Skills: He was able to restore the Sokai Faction from scratch, as well as convince Rokkaku Kirie to help in assassinating Okita Sougo, so it can be said that he is at least good at it.
- Okita Sougo: Sougo was responsible for most of the deaths of the Sokai Faction members during the Rokkaku Incident two years ago, among those deaths, Tendou Soutatsu's brother. Since then, Soutatsu was keen on getting his revenge on Okita Sougo for eradicating his faction.
- Kagura: During the Rokkaku Arc, the renewed Sokai Faction captured Okita Sougo and Rokkaku Kirie, as well as Kagura, who was with them, even though they had nothing against her before. Sougo, Kagura and Kirie free themselves, and later on, Sougo stays behind while an injured Kagura escapes with Kirie.
- Rokkaku Kirie: He convinced Kirie that Sougo killed her father. When he died, the bank that stayed for her and her mother to take care ended up bankrupting, since nobody wanted to sleep in a place where such massacre had occurred. Shortly after, her mother died, probably from stress, which left her alone. Since Soutatsu wanted to kill Sougo, he manipulated Kirie into helping him. Though initially she'd only be a bait, she tried to kill him herself, which served as an excuse for him to betray her and capture her as well as Sougo and Kagura.
During the events of the Rokkaku arc, it is revealed that he is behind the plan to kill Okita Sougo, as a revenge for having lost his brother and friends two years ago during the Rokkaku Incident. After finally showing himself as the new leader of the Sokai Faction and the real creator of the plan to assassinate Sougo, he explains what he saw during the Rokkaku Incident, as he was hiding: A bloodied Sougo with Rokkaku Muneharu's dead body to his feet telling Kamiyama not to tell a word about what really happened, and the story would be that he was caught up in the middle of the battle and ended up killed. After telling the story, he captures Kagura, Sougo and Kirie, and takes them to an abandoned building, which served as his hideout. It is supposed that he captured them instead of just killing them to lure the Shinsengumi into a trap.Once they're there, he began to tell Kirie that her father was actually not just a civilian, and was actually helping the Sokai Faction, but he was interrupted by Kagura, who knocked her unconscious, to keep Sougo's secret. As he explained what were his motivations to keep the secret, Sougo interrupted himself abruptly and shouted he wanted to go to the bathroom, starting a huge scandal. As Soutatsu got worried he'd make a huge mess, he ordered one of his comrades to go get something Sougo could use to poop on, when the man went to search for a chamber-pot, Sougo suddenly stopped screaming, putting on a relief face and saying he was okay now. After hearing this, Kagura got disgusted and threw up massively, causing an even bigger confusion, which led to Soutatsu and some of his comrades throwing up as well. During the confusion, a sword was thrown near Sougo, and he used it to cut the ropes tying him, Kagura and Kirie, and they escaped together, much to Soutatsu's displeasure. He ordered the Sokai to follow them, but they couldn't move in a slippery floor full of vomit, but even with that advantage, eventually they caught up to the escaping trio, hurting Kagura's leg in the process. Since Kagura couldn't fight, Sougo told her to escape with Kirie as he'd stay behind and slow the pursuers down. Soutatsu pointed that it was just like two years before, as he was fighting alone to protect his comrades, except that this time around the numbers against Sougo were much bigger. Sougo told him that the numbers didn't matter and he'd slay anyone that came his way to protect his friends. Soutatsu ordered the attack on Sougo, and the faction began attacking him at once, but one by one, they were all defeated by Sougo. After killing lots of Sokai members, Sougo put his sword down with a weird look on his face. Realizing this, Soutatsu ordered more people to attack him, only to be surprised by the Yorozuya and the Shinsengumi, who had downed the rest of his men. Taken over by fear, Soutatsu mindlessly ran in Sougo's general direction, only to be knocked unconscious by Sougo, and later captured by the Shinsengumi.
|Fight||Outcome||Time it Occurred|
|Okita Sougo vs. Soutatsu Tendou||Loss||Episode 187|