He is the younger brother of Hoou Gundam, and later Sho Gundam. He is a "Thunder" warrior chosen by the "Armor of Thunder", and together with his brother Hoou, he continues to fight the Dark Army while searching for the remaining "Earth" bushou. By chanting "Thunder" during battle, the "Sacred Treasure of Thunder Emperor" appears on his back. The Sacred Treasure of Thunder Emperor is a legendary treasure that is said to have been used by the Thunder Emperor, one of the Three Bushous, and converts the electric energy collected by his thunder wings into combat energy. When the third bushou, Alex, was found, he made his brother the Daishogun, and when they faced the threat of the return of darkness, he searched for the Four Beast Kings, and always supported his brother. He has been best friends with Zaku since childhood, and they even recognize each other's strengths.