BackgroundSakumo was a famous and powerful ninja of Konohagakure who, during his life, was greater than even the Sannin. His son, Kakashi, idolized him and sought to become just as great a ninja as his father; his wife had died when Kakashi was very young. Five years before the events Kakashi Gaiden, Sakumo and his team were sent on a mission of great importance to Konoha. When his teammates' lives were endangered, Sakumo chose to abandon the mission in order to save them. He was disgraced when he returned home, shunned by everyone in the village, even those he had saved. Dishonored, Sakumo fell into a deep depression, as well as a drop in his skills. Eventually, he committed suicide, which caused Kakashi to live strictly according to the Ninja Code during the time before his last mission with Obito. Sakumo's soul waited in an area of darkness, for a chance to meet up with his son and be set free.
AppearanceSakumo's appearance has regularly been compared to that of Kakashi, often when Kakashi is mistaken for his father. Like his son, he possessed the same silver-colored spiky hair with the addition of a long ponytail similar to Jiraiya's, and a mess of hair on his head that hangs over his forehead protector. His facial features are more distinguished compared to Kakashi's visible ones. He wore a standard Leaf ninja uniform and flack jacket with the addition of a distinctive short white left sleeve with red jagged edges.
PersonalitySakumo was a very kind and loyal man. Despite his tremendous fame and power as a ninja, he was a very humble man, which made his only son Kakashi truly look up to and idolize him. He had a deep devotion to his country and an even greater commitment to his allies and loved ones to the point he would put their well-being before anything else. His commitment was so great that he would sacrifice the completion of a mission in order to save his teammates which led to him being a public figure of hate and ridicule.
Pain Invasion arc
After Kakashi is killed by Pain during the invasion of Pain, he finds himself in an area of darkness, where Sakumo meets up with his son to talk of his life. Sakumo lamented the idea that they both died young; though not as young as his wife. Kakashi said that he understood his sacrifice for the sake of all the villagers. Then Kakashi finally forgives Sakumo and said that he was proud of him. When a ray of light beamed down upon Kakashi, Sakumo told Kakashi that he has still a lot of things to do and Sakumo was glad that he was able to speak to Kakashi and that he's thankful that his son had forgiven him. After Kakashi disappears, he said that he can finally move on and see his wife again.
AbilitiesLike his son, Sakumo was a gifted shinobi praised for his talents in the ninja arts even by the likes of Minato Namikaze, the Fourth Hokage. In battle, Sakumo was a truly powerful shinobi, his prowess surpassing that of the Sannin. The mere idea of facing Sakumo brought fear to enemies, as shown from the reaction of an Iwagakure shinobi initially believing Kakashi to be his father. His primary weapon during battle was a tanto called the White Light Chakra Sabre that would emit a trail of white chakra when swung, earning him the nickname "Konoha's White Fang". After he died, he left his tanto to Kakashi, which was later on cut in half when Kakashi fought an Iwagakure shinobi.