The dead Uchiha Izuna was too obsessed with his obsession. When he opened his eyes, he saw his favorite brother being stabbed from behind by Senju Hashirama. The proud brother fell into the water and roared in pain. He came back to life after the Third Ninja War and was permanently fixed at the age of 24.
Knowing from Black Zetsu and Obito that Madara's last wish was the Eye of the Moon project, Izuna put on a mask and determined to secretly manipulate the ninja world for Madara's plan. Finally, he started four battles with Obito and resurrected Uchiha Madara!
Intention: Izuna is always behind Madara