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.
Proper credit goes to spikeystudio for the original project, MinecraftFan11 for the remix this was based on, and everyone else who remixed! I added TONS more sounds to make the fight more lively. you'll definitely notice them.