Yuu Amano (天野 ユウ Amano Yuu?) is Nene Amano's younger brother, and the reason that she is in the Digital World. Some time ago, Yuu was tempted into the Digital World by AxeKnightmon, who told him that no one could get hurt in the Digital World, and without knowing about his role in Yuu's disappearance, Nene later accepted AxeKnightmon's offer to serve him in exchange for his help rescuing her brother. It is soon revealed that Yuu is actually a willing partner to AxeKnightmon, and the true General of the Twilight army. However, after forcing Yuu to accept that death and suffering still exist in the Digital World, Mikey eventually convinces Yuu to leave AxeKnightmon and defect to the Xros Heart United Army.