Hybrid

Dear Princess Celestia, the group boss Hybrid is even harder to kill than all seven of Fullmetal Alchemist: Brotherhood's Homunculi combined! He can only be critically hit by Sonic attacks, has overpowered attacks, and regenerates himself. We're gonna need your help in order to finally destroy him. Fire and explosive attacks, which you personally have, are his weakness. You can also heal the entire team and remove debuffs as a quick action. Then there are the side effects of your Solar Beam (Blinded, Poisoned, Staggered, Off-balance, Winded, Cornered, Incapacitation, Intimidated, Exhausted, Iso-8 Corruption, Halitosis, or in extreme cases, super powers.) And bring my Crash Man too. He's immune to bleeding and has explosive attacks.