F-Rank Ox? I'm Thunder

F-rank beast soul. Yellow Ox. The weakest of the weak. But Hale Dunn has a secret: a system, a past life, and a thunder soul buried within. One breakup. One trigger. One storm. Now, he fights alongside an Ice Phoenix and a Thunder Leopard against conspiracies, dark invaders, and anyone who calls him "Old Ox." They wanted trash. They got the Thunder Sovereign.