Gunichi was once the chief retainer of Lord Mifune. Attending Usagi's first tournament with his lord, he kept a close eye on the youth after his victory. Challenging him to a dual to test his skill, the two fought to first blood. Interrupted by Dogora fencing school students, they killed their would be ambushers and called the duel a draw, both their swords having tasted crimson.

Usagi and Gunichi become firm friends, and at the battle of Adachigahara protect the flanks of their lord. Gunichi and Usagi fight like demons to protect their lord, however when the battle goes badly for them, Gunichi shows his true colors and runs from the battle, deserting Lord Mifune. Usagi Stays with his lord, telling him that Gunichi was slain, saving his lord the loss of face.

Years later, Usagi encountered Gunichi in his wanderings. There could be only one outcome from the encounter, and Usagi left Gunichi laying in a pool of his own blood.