Derek

Derek is a character in Pokémon J. He appears only in Pokémon J, not Pokémon M. He is the oldest in Jason's family.

Description
'Derek... the master of darkness... to which... all Dark-types... will obey... the Dark-type Gym Leader... (Translation: Derek is the master of all Dark-type Pokémon and is the Gym Leader that uses Dark-type Pokémon in battle.)'

Physical Description
Derek has shaggy bangs that drape over his face. He usually wears a gray sweater and dark blue jeans. He doesn't look that scary, but his battle skills are deafening.