The Tendoushuu were a group of Amanto that not only controlled large parts of Gintama 's universe but are the true rulers of Earth with their main base of operations in Edo, Japan. The series established early on that they were one of the main villains in the story who influenced many of the actions and lives of most protagonists and antagonists.
With the discovery of a potent energy source named Altana, originating from planets, technology advanced by leaps and bounds. Many planets went to war over it which resulted in a group of wealthy Amanto forming an organization that in theory was meant to monitor its usage. But since they owned much of the planets that held Altana, it meant in practice that they conquered worlds with the potential energy, with Earth being the most recent conquest. It could be inferred that they were behind the decision to force Japan to open its borders to the Amanto. It was revealed that they also helped the Bakufu defeat the Joui rebels during the Joui Wars.
Ten years before, during the late Joui Wars, they encountered an immortal who willingly gave them his immortality (turning them semi-immortal) and in return, he became the new member of the Tendoushuu. In the years since, they have established themselves as the true rulers of Earth, especially Japan. The biggest symbol of that control is the Edo Terminal, which sits on a gate over the biggest of Earth's Altana holes, an area where Altana leaks out of.
It is established that they run many shady businesses, like Rengokukan. They also control many human and Amanto government officials, including the 13th Shogun, Tokugawa Sada Sada. It is also implied that they have indirect control over the Harusame and probably other space pirates.
For the past twenty years or so, they gained control of the Tenshouin Naraku, that was further cemented when its former leader, Utsuro, became a Tendoushuu member and his strongest loyal disciple, Oboro became the new leader.
The Tendoushuu are an organization lead by twelve Amanto (actually 11 Amanto and one human), commonly shown in a room sitting in a circle on top of tall pillars mocking their allies and enemies while boasting about their superiority.
They controlled an underground arena called Rengokukan. When Sakata Gintoki came to fight against Ojinishi in the arena, one of the Tendoushuu watched the fight and realized that Gintoki had the eyes of a real samurai. Shortly after, the Shinsengumi and Yorozuya put an end to the arena as the Tendoushuu member withdrew.
The priestess sisters, Mone and Ane, reveal to the Yorozuya about how the Tendoushuu took control of their former home to turn it into the Edo Terminal. Their shrine-home was an opening to the life energy source called Ryuumyaku (Dragon Veins). In the later Rakuyou Arc, Ryuumyaku is revealed to be another name for the Altana.
The group were observing Sahadaru's berserk state, though concluded it as no grand threat to them.
The Tendoushuu are shown to have control over Sada Sada and the Naraku. They arrive to save Sada Sada from the revolt to his power. But his nephew, Tokugawa Shige Shige decides to stop them by resigning as shogun so his uncle will be able to be punished by law. Shige Shige is later temporarily restored to power.
In their ship, they discuss how their puppet Sada Sada had been brought down by his own ego and pride. The Naraku leader, Oboro, tells his masters that the Tendoushuu's true enemies were the students of Yoshida Shouyou. This is shown by how Gintoki's influence had lead to the "revolt" in the first place and how Takasugi Shinsuke killed Sada Sada and is implied to be in league with the Hitotsubashi Faction, later confirmed in the Shinigami Arc.
The Tendoushuu arrive in the Iga ninja village to confront Shige Shige. They reveal that they had a hand in getting Hitotsubashi Nobu Nobu to betray his alliance with the Kiheitai to become the new Shogun and their puppet. They also had a hand in getting the Harusame to betray one of their own divisions, the 7th Division, lead by Kamui. This greatly cripples the Kiheitai- 7th Division alliance, who end up on the run.
They were forced to withdraw when Shige Shige's faction was saved by the arrival of Matsudaira, Shinsengumi and the other police forces. After Nobu Nobu succeeds in assassinating Shige Shige, the group mocks the ex-shogun for not knowing his place, ruling as their puppet.
A Tendoushuu member named Utsuro, arrives at Kokujo Prison Island after the group learned that someone had betrayed them and the Bakufu and sparked a rebellion. The member also came to fight another insurgent (Gintoki) who have arrived on the island earlier. Ultimately, the rebels were forced to flee the island after getting what they want, their leaders (Matsudaira, Kondou, and Katsura) but lose Isaburo in the process, even though their fight was separate from Isaburo's.
Imai Nobume reveals the history of the Tendoushuu along with a little of the past of its member, Utsuro.
Utsuro continues to chase after the insurgents, Katsura, Gintoki and their groups, who are now joined by Sakamoto Tatsuma and his Kaientai. By using his newly acquired Harusame, he also goes after Takasugi, his Kiheitai and Kamui and his 7th division to the Kiheitai's hideout, the planet Rakuyou. He becomes interested in fighting Umibouzu. He retreats with his remaining pirate/ Naraku forces after getting what he wants (his fight with the hunter) to Earth where he is summoned to meet his fellow Tendoushuu. Utsuro's disciple, Oboro tells his fellow disciples more about Utsuro's past and how the Tendoushuu maintain their monopoly on Altana. Only they have the keys, unique permanent tattoos on their palms, to open and close the Altana Gates and it is impossible to take or receive them without their willing consent.
It is revealed that the entire arc was a distraction by Utsuro so that the Tendoushuu would fail to see his true goal, using the keys forbidden to him to self-destruct a few planets' Altana Gates. This will enable the other planets to distrust and further hate the Tendoushuu, leading them to attack their base, Earth, sparking a war. The keys were given to him by some of the members themselves as a bargain to reverse their decaying bodies, caused by the failure to cope with his immortal blood. The decay had lead to them staying alive despite their bodies falling apart, including losing the limbs that contained the keys.
Over a month passes after Utsuro's meeting with the Tendoushuu at the end of the Rakuyou Arc. The Amanto whose planets were devastated by the destruction of the Altana Gates formed an army called the Altana Liberation Army and had liberated planets from the Tendoushuu's control until reaching Earth to both liberate (control) it and find the group, who have vanished during this time. As Nobu Nobu negotiated with the army to bring the Tendoushuu to them, it is revealed that some of the Army already knew the Tendoushuu's whereabouts. It is implied that almost immediately after the Tendoushuu meeting, Utsuro blew up the ship and it crashed on Earth. Utsuro and the Tendoushuu survived but unlike Utsuro, the Amanto group's bodies were mostly destroyed, leaving mostly pieces behind. The Army found them and had kept them in pods ever since.
Despite their mission being accomplished, one of the Army's leaders decides to continue the war with Earth to satisfy their revenge and chooses not to tell the rest of the army and Nobu Nobu about them.
When the army was defeated, a faction rebelled, stealing the group's remains and fleeing. In despair due to lost comrades and loved ones and being aware of the potential immortality contained within the Tendoushuu, the faction joined a religious cult known as Tengenism, the worship of immortality. They used their technology to restore the Tendoushuu's bodies, though some are killed by Takasugi before fully reviving. The group manipulates the worshipers into making them the leaders, with the promise of making the worshipers live forever. The remaining Tendoushuu spent some time searching for, then finding a reborn Utsuro, afterwards, secretly draining Altana from some planets to restore him from their undetectable ship, Kuyou.
They reach Earth to drain its Altana from the halfway rebuilt Edo Terminal, but are caught by a surprise attack before crashing into the it. Mostly unscathed, they disembarked to secure the tower while dismissing their potential enemies. While Utsuro revives by growing a new core, the trio members realize that they have been influenced then later possessed by the evil Utsuro personality. This allowed the personality to have another chance to destroy Edo and the universe while bringing despair. Two of the members, thanks to gaining Utsuro's fighting skills, fight against Gintoki and the weakening Takasugi. They are vaporized by the rampaging Altana. The last sees Utsuro revived and offers to help with the immortal's goals, just to be killed by the new personality inhabiting it, Shouyou.