Dan was Shizune's uncle and Tsunade's boyfriend, whom she met after he spoke out in favor of her proposal to assign medical ninja to each squad shortly after her brother's death. Because his younger sister died during one of the many raids on Konoha, he aimed to be able to better protect his loved ones. For this end, he wanted to become Hokage. He died during a battle due to hemorrhage, despite Tsunade's desperate efforts to save him. His death made Tsunade hemophobic and made her leave Konoha together with Shizune. Dan would later become one of the people Orochimaru offers to bring back to life in exchange for Tsunade's help, though she ultimately refuses.