Arc 1Seiichi’s Rise and the Uchiha’s Claim
Seiichi strengthened the Uchiha Clan, exposed Root’s illegal power, and helped his family awaken formidable Mangekyō abilities. After the war, he asserted the clan’s rights and ended by demanding the Sharingan Obito had entrusted to Kakashi.
- Seiichi used the blood of 20,928 Uchiha to create a complete bloodline serum, transforming his body and strengthening his Sharingan.
- As the Third Shinobi World War raged, Seiichi raided Orochimaru’s laboratory and later developed Divine Medicine that awakened his Mangekyō Sharingan.
- Seiichi confronted Root after its members attacked him, invoked the Konoha Military Police Force’s authority, and forced Hiruzen Sarutobi to disband Root.
- Seiichi treated his family and trusted Uchiha with the Key, while Fugaku, Mikoto, Shisui, and Itachi trained and revealed their abilities.
- Seiichi, Fugaku, and Mikoto tested their Susanoo near the Land of Whirlpools, where Seiichi revealed his Perfect Susanoo and destroyed a mountain with its Tailed Beast Bomb.
- After the war, Seiichi promised aid to injured Uchiha and their families, then revealed his Eternal Mangekyō Sharingan to the clan elders.
- At the postwar meeting, Seiichi announced that he would reclaim the Uchiha Sharingan held by outsiders, and Kakashi refused to give up Obito’s eye.
- Seiichi insisted that the Sharingan could not remain with an outsider unless the entire Uchiha Clan unanimously agreed to an exception, and Hiruzen Sarutobi and Minato Namikaze accepted his refusal to yield.