Preemptive: 4000 Damage to your face
HP: 1, 180, 000
Attacks every turn for 10,000
Under 20%: Attacks for 25, 000
Mihawk isn't too bad, but if you can't beat him, you probably can't beat any other Raid Boss.
He is able to be beaten by a Vivi Laboon team.
To beat him legitimately, just use your strongest units with a Golden Pound Usopp.
I only have 1 team below because there are so many teams that can beat Mihawk there really is no point in showing too many teams. This team is free to play and the levels are very manageable. Just hope you get decently with orbs.