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Chief is an interesting trainer class that seems to be a beta object. The only way to fight a "Chief" is through the Old Man Glitch when the player's name contains a dash in the third, fifth, or seventh letter slot. Chief's sprite looks identical to that of a Scientist. The only time the word is said in the game is in Celadon City, by a Team Rocket Grunt.

Generation I-introduced trainer classes
Beauty | Biker | Bird Keeper | Black Belt | Boss | Bug Catcher | Burglar | Champion | Channeler | Cooltrainer Cue Ball | Elite Four | Engineer | Fisherman | Gambler | Gentleman | Hiker | Jr. Trainer♂ | Jr. Trainer♀ | Juggler Lass | Leader | PokéManiac | Trainer | Psychic | Rival | Rocker | Rocket | Sailor | Scientist Super Nerd | Swimmer | Tamer | Youngster
Beta classes
Chief | Pokémon Prof.