In Pokémon Sun and Moon, a Trial Captain is the highest ranking member of a trial of The Right of the Island Challenges. Each trial captain is assigned in different parts of the Alola Region.
List of Trial Captains
Mallow
A Trial Captain who specializes in Grass-type Pokemon.
Lana
A Trial Captain who specializes in Water-type Pokemon.
Sophocles
A Trial Captain who specializes in Electric-type Pokemon.
Kiawe
A Trial Captain who specializes in Fire-type Pokemon.