Best build for Hector?

Wary Fighter and QR seal.

A. Distant Counter
B. Vantage
C. Threaten Defense
Special. Bonfire
I recommend either swap or pivot as well. Pivot is very spicy to use on non armor emblem teams, with swap generally being better for armor teams.

I highly recommend the Wary Fighter/Quick Riposte build. It is Hector's niche that no other character released to date can fill, not even Valentine Hector.

I just thought of another B skill that kicks my ass in arenas. When a Hector has WoM. D: it’s unexpected and it seriously kicks my strategies out the door.

As Hector does.

Hector has a variety of options, mainly centering around his B and seal slots. His A slot will always be distant counter, his weapon Armads. And his C slot is either threaten atk or threaten def for general use, or an armor buff for armor emblem. His support is typically either pivot or swap, but I’ve seen some use reposition; entirely your discretion based on play style. His special typically is bonfire or Ignis, arena builds run Aether for higher scoring potential.

B slot is where things get interesting, as that will dictate his purpose. Enemy phase builds desire wary fighter combined with a QR seal, vantage, or vengeful fighter (not really recommended unless you decide to swap his prf weapon out for slaying axe). Player phase builds want bold fighter, wrath, or desperation/brash assault combo (I have seen this once in AA, and it looked extremely strong). Some other general ideas include guard, wings of mercy, and escape route.

Seal choices are at your discretion if you run a build that won’t use the seal in a combo with the B slot.