In full Biju form, the personality of Kokuo himself comes to the forefront — quiet, reserved, and extremely polite, or working in symbiosis with Han. In the case of the 4th Great Ninja War period, it did not matter — both Han and his beast were suppressed. The beast rarely speaks, but when it does, it uses the old-fashioned "watakushi," making it sound emphatically courteous. The tailed beast's pride within him is strong, and the thought of being used as a puppet fills Kokuo with deep disgust. That is why, the moment he briefly broke free from Tobi's control, he immediately tried to attack his enslaver. In calm moments, when the need for battle receded, Kokuo gave the impression of a peace-loving creature desiring only silence and solitude. He does not seek battles, and after the war ended, he announced that he wanted to hide in the forests, away from human squabbles.