Master Trainer

are Trainers that appear in Pokémon: Let's Go, Pikachu! and Pokémon: Let's Go, Eevee!. These trainers each specialize in training only one of the original 151 Pokémon (alongside Meltan and Melmetal, bringing the number to 153), holding the title of Species Master.
After becoming Champion, they can be found throughout Kanto. They have a similar appearance to other Trainer classes found in the game, though they sport mainly red clothing and have an icon above their head showcasing the Pokémon they specialize in. To challenge them for the title, players must battle the Master Trainers with the same species of Pokémon as them. The Pokémon they use are normally high leveled, have max IVs in some stats, and hold lots of AVs.
The Master Trainers that specialize in Ditto, Legendary Pokémon, and Mythical Pokémon do not battle the player, but instead grant the player their title once the player shows them the Pokémon they specialize in. However, the Pokémon shown must have a high enough CP in order to gain their title.
Upon battling and defeating at least six Master Trainers, the player will be able to battle Red at Indigo Plateau outside of the Pokémon League. After defeating Red, the player gains the title of Battle Master. If the player defeats all of the Master Trainers, with the exception of Master Trainers that specialize in Mythical Pokémon, they will earn the title of Grand Master.
==Trivia==
*Lass Marge, the Jigglypuff Master Trainer, takes the place of the Jigglypuff NPC previously seen in the Pokémon Center of Pewter City. Said Jigglypuff NPC is relocated to the Pokémon Center on Route 4.
*The Onix used by Hiker Jim, the Onix Master, knows the move Wrap. Onix can not legitimately learn this move.
*The names of Scientist West and Scientists Keaton, the English names for the Zubat and Golbat Master Trainers, are references to Adam West and Michael Keaton respectively, two actors who have both played the role of Batman.
==Sprites==
Ace Trainer Master VS PE.png|Ace Trainer Master VS Sprite
Beauty Master VS PE.png|Beauty Master VS Sprite
Bird Keeper Master VS PE.png|Bird Keeper Master VS Sprite
Black Belt Master VS PE.png|Black Belt Master VS Sprite
Bug Catcher Master VS PE.png|Bug Catcher Master VS Sprite
Hiker Master VS PE.png|Hiker Master VS Sprite
Lass Master VS PE.png|Lass Master VS Sprite
Psychic Master VS PE.png|Psychic Master VS Sprite
Scientist Master VS PE.png|Scientist Master VS Sprite
Youngster Master VS PE.png|Youngster Master VS Sprite