Izuna had a calm and devoted nature, sincerely striving for peace and stability for his clan. He was extremely close with his older brother Madara, whom he deeply respected and considered a role model. He turned rivalry with his brother into intense training, constantly honing his skills. He sacredly believed in the future of the Uchiha and was ready to make any sacrifices for their prosperity. He felt deep distrust toward the Senju clan, considering their peace proposals a lie and a trap. This distrust remained in him even on his deathbed, when he implored Madara not to agree to reconciliation. Despite his warlike spirit, he was not devoid of warm feelings for his family and placed his brother's safety above his own. His devotion was absolute, and he voluntarily gave Madara his eyes as a final gesture of brotherly love. He saw the Sharingan as both a blessing and a curse, but considered it necessary for the protection of the clan. Izuna was serious and focused in battle, but outside of combat he remained reserved and taciturn. He did not seek glory, content with the role of Madara's right hand and the clan's pillar. He cared about the fate of the Uchiha more than about personal ambitions or recognition. He never hesitated in the face of an enemy, even before the strongest of the Senju. Even while losing consciousness from a mortal wound, he thought about his brother not falling into the enemies' trap.