Don Justo Takayama, also known as Takayama Ukon, is a Christian Daimyo and a Japanese samurai who aided the Oda Faction during the Battle at Kiyomizu Temple. He and his clan joined Nobuna Oda's alliance due to her religious tolerance and the rescue of Louise Frois, a leading Christian in Japan, by Nobuna's retainers. He is also the lord of Sawa Castle and Daiymo of the Takatsuki region.
As heir of the Takayama clan, he eventually rose to the Daiymo of his clan's land.
As Daiymo of Takatsuki, his domain bordered on the free city of Sakai, one of the richest cities in Japan and both a center for the trade with foreigners and the Christian religion. After he came into contact with the religion of the Barbarians, he converted from honest conviction. He was baptized as Don Justo Takayama. Thereby, he also became one of the few converted Christian Daiymos in central Japan, and a very faithful person who would rather die than give up his religion. Sometime later, he met Louise Frois, a Portuguese nun and missionary who resided in Sakai. From this time stems his respect and admiration for the nun that would help Louise later on to call him to arms when her allies were in danger.
After the coup of the Miyoshi Three and the following occupation and destruction of Kyoto, Louise was rescued by Nobuna Oda's retainers Yoshiharu Sagara, Inuchiyo Maeda, Goemon Hachisuka, and Hanbei Takenaka from bandits. Convinced by Yoshiharu that Nobuna Oda would be the one to save Japan and end the wars, she allied herself with the Oda Faction. The capital was eventually liberated from the Miyoshi Three and secured by the Oda Faction, ending the reign of terror within the city.
However, Nobuna's plan to unite Japan was in danger when the troops of the Miyoshi Three counterattacked and besieged Kiyomizu Temple, in order to kill the Imagawa Shogun who was allied to the Oda and drive Nobuna's army out of Kyoto. The desperate Oda Daiymo without any troops within reach sent a message to Louise and asked her for help. The nun agreed and gathered all Christians around Kyoto, notably Don Justo Takayama and a powerful Samurai of Sakai, Joaqim Konishi. Together with a army of free Christian Ashigaru under Louise's leadership, Takayama's and Konishi's troops entered Kyoto and defeated the army of the Miyoshi Three, rescuing Nobuna and forcing Hisahide Matsunaga to surrender.