From Bulbapedia, the community-driven Pokémon encyclopedia.
Kerrigan (Japanese: カワダ Kawada) is a character of the day from the episode Duels of the Jungle!.
He is part of the Wilderness Guard Core and explained to Ash and his friends that the stray Weavile that attacked them was once part of a group of Sneasel and Weavile.
He also helped heal Aipom after she battled with the Weavile. Unlike most other characters of the day, he didn't have any known Pokémon with him.