Naruto: Wooing Tsunade from Day One! Novel

A failed author transmigrates into the Naruto world as the younger brother of Sakumo Hatake, the White Fang of Konoha, making him the uncle of Kakashi. Armed with a cheat ability that enhances cellular activity, he encounters Tsunade at a Jonin meeting just before the Second Shinobi War, where he supports her proposal ahead of Dan Kato. This marks the beginning of his romantic pursuit. Throughout the war, he wins her heart with his relentless efforts. Tsunade finds herself repeatedly drawn to him, wondering why she keeps losing to his charm. Kawakaze Hatake, as he is known, remains humble about his accomplishments, attributing his success to wanting to live a longer life. Meanwhile, Kakashi idolizes his uncle, considering him his greatest inspiration, though Kawakaze prefers to keep his remarkable abilities and achievements low-key and out of the spotlight.