It's simple. Add yourself attacking him. Just a few rules though: -Have a health variable. -Don't be overpowered. -Don't give yourself a spammable heal.
Note: when I tested Jorge (the big gray person), He took way too much damage, cause I programmed it to take several damage to protection... He died during testing. He's not that OP like some others I find... :P Note II: Sonic EXE is big cause Jorge does a lot of fast bullet damage, everyone has increased damage.