The Head Guardian is a boss that wields the Sky Blue Katana and resided in the third floor inside of the Sky Castle in Skypea. The Head Guardian quest has a level requirement of 135.
Has a Spawn time of 5-10 min, biggest chance that its 10 min
Tip:If you have barrier you may spam X at him from the bottom, He wont be able to damage you.
Tip for 1ss Users: If you have 1ss, use your Dragon Blaze to hit the boss from beneath the floor hes on, the boss shouldnt be able to hit you as long as you dont jump as his green AOE attack can reach you if you jump. Reminder to also use your green slash ranged move as it simply increases your total damage output towards the boss, a strategy I recommend using is to have the sword user below and having a friend with Black Leg, the Black Leg user will use party kick course while all the npcs are grouped up as they are going for the sword user, when the party course is about to end, the sword user uses their ultimate so that the npcs attention goes back to the sword user and the black leg user can wait for cooldowns. Rinse and repeat until the boss is dead.
If you use Fishman Karate: You basically just win. Spam your Shark Barrage and Water Prison at him and his guards from below the floor until he dies.