Heal up then head east along the road, where Marnie will give you Piers' league card. Piers is the gym leader and he's a big fan of Dark-type Pokemon, which are weak to Fighting, Bug, and Fairy-types.

Pokémon Sword and Shield: how to beat Piers, Spikemuth's Dark Gym Leader. Piers is the only Gym Leader in Galar who doesn't Dynamax or Gigantamax his Pokémon - in fact he refuses to do so out of ...