Vernon Evans is the Grass type Gym Leader of Delwis, being the first one that Emmet encounters. He's a wise old man, who loves taking care of his garden and his Pokemon. He originates from the Galar region, and he's very kind and caring towards everyone, including his protege, Sage. 

Vernon is British (as he's from Galar, the region based on Britain). I imagine he sounds a bit like David Attenborough.