From Bulbapedia, the community-driven Pokémon encyclopedia.
Stat Trainers is a fan term for a group of five Pokémon Trainers - Cheryl, Mira, Riley, Buck, and Marley - who specialize in Pokémon that excel in a certain stat.
In the games
Double Battle with Marley
The stat Trainers first appeared in Pokémon Diamond and Pearl, where each is encountered at a certain point during the player's journey. Unlike other Trainers, the stat Trainers ask the player to help them to navigate their way through a certain area, participating in Double Battles against other Trainers and wild Pokémon, and healing the player's Pokémon after each battle.
After the player has defeated the Elite Four, the stat Trainers that the player has encountered so far (only Cheryl is required to be encountered during the game's storyline; the others are optional) will be waiting in the Battle Tower to participate in tag-team Double Battles.
In Pokémon Platinum, in addition to reprising their role from Diamond and Pearl, the stat Trainers the player has encountered will also appear in the Battleground in the Survival Area as potential opponents. Riley and Buck are also now required to complete the game's storyline, with both of their scenarios involving Team Galactic.
The stat Trainers also appear in Pokémon HeartGold and SoulSilver as tag-team partners in the Battle Tower.
In the anime
All five Trainers have appeared in the anime, doing so in the same order they can first be encountered in the games.
Cheryl was the first to appear, in Some Enchanted Sweetening! and the two episodes that followed. As in the games, she traveled with Ash and his friends through the Eterna Forest. After finding the Honey she was looking for in An Angry Combee-nation!, she left the group.
The next to appear was Mira, in Sandshrew's Locker!. Unlike in the games, she was not lost in Wayward Cave, but instead needed Ash and his friends to help her with their Water-type Pokémon to retrieve her Sandshrew from her sunken school. After this was done, she had her Abra teleport the group to Hearthome City.
Riley made his appearance more than 50 episodes later, when Ash journeyed to Iron Island in Steeling Peace of Mind!, after facing Byron. Like Ash, Riley has the ability to use Aura. He and his Lucario, along with Ash and his friends, stop Team Galactic's plot to discover the location of the Spear Pillar on Mt. Coronet while attempting to calm the Steel types that are disturbed by the beam the evil team is sending at the mountain in the next episode.
Marley appeared in Keeping in Top Forme!, where she was helping a Shaymin get to a field of Gracideas. Team Rocket were after Shaymin, and Marley, along with her Arcanine, helped Shaymin escape by hiding it in her basket. Marley had asked Brock, along with Ash and Dawn, to escort her to the garden to find the field of Gracidea flowers for Shaymin.
Buck appeared in Bucking the Treasure Trend!, looking for a hidden treasure near Lily of the Valley Island.
- All of the Pokémon used by the stat Trainers when they team up with the player are Pokémon that, as of Generation V, have evolved once.
- All the stat Trainers' names are based on a variety of grains in the original Japanese and all translated versions.
- The stat Trainers are the only Pokémon Trainers with animated sprites that use the standard Trainer battle music prior to Black 2 and White 2.
- The stat Trainers are the only Trainers, aside from the player, allowed into the Battleground without being Gym Leaders.
- There is no stat Trainer for the Special Defense stat.