Also known as: possibly Houjou Ujihide (北条氏秀), Houjou Saburou (北条三郎), Saburou Kagetora (三郎景虎)
Historically: Uesugi Kagetora was the seventh son (sixth to survive to adulthood) of , younger brother of , , , , , and older brother of . His mother was the sister-in-law of , a vassal of the Houjou Clan (other sources say , 's principle wife). It's likely that he and Houjou Ujihide were two different people and that Ujihide was the son of and living in while Saburou was living in , so most historians refer to him as Houjou Saburou when describing his early life.
As a child, he was sent into the priesthood at in , then sent as hostage to of the Takeda Clan in the three-way alliance between Houjou, Takeda, and Imagawa formed in 1554 (though this last point is now in dispute, as it is told only in the and recorded in none of the Takeda Clan records.)
He was adopted by his uncle in 1569 and married Genan's daughter.
When the Houjou and Uesugi clans formed an alliance in 1569, Saburou was sent to in an exchange of hostages with . (At first, the hostage was set to be 's third son Kunimasumaru, but Ujimasa could not bring himself to send off his son, who was then still a baby.) Saburou was sent to the Uesugi clan in early 1570. Kenshin, who never married, developed a liking for the handsome and intelligent Saburou. He married his niece , the daughter of and older sister of Nagao Akikage () to Saburou, gave him the name Kagetora (a name that had once belonged to Kenshin himself), and adopted him into the Uesugi Clan.
When Kenshin died suddenly in 1578 without naming an heir, Kagetora and Kagekatsu, similarly adopted by Kenshin, fought for succession to the position of clan head (the ). Though Kagetora held the early advantage with the backing of Uesugi vassals such as , , , and the Houjou Clan, the tide of the battle turned with 's betrayal to Kagekatsu's side.
When the fell in 1579, Kagetora attempted to escape to , but was betrayed at by and committed suicide. His wife committed suicide along with him (though there are also accounts that she remained behind at the and committed suicide there when her brother Kagekatsu refused Kagetora's surrender.) His oldest son died at the hands of Kagekatsu's troops along with , and the rest of his children were believed to have died along with their parents.
In Mirage of Blaze: He was born to and as their eighth (seventh to survive to adulthood) and youngest son. After his death in the , he was charged by to become in order to ensure that the peace of Japan is not disrupted by the as the leader of the and the commander of the .
