From Bulbapedia, the community-driven Pokémon encyclopedia.
The Ball Guy (Japanese: ボールガイ Ball Guy) is a character introduced in Pokémon Sword and Shield.
In the core series
The Ball Guy is the mascot of the Galar Pokémon League. Over the course of their Gym Challenge, the player will meet a person dressed in a Ball Guy mascot costume in or near each Stadium Lobby, who will give them a variety Poké Ball with each meeting. It is later revealed that the person dressed as the Ball Guy is not sanctioned by the Pokémon League and has been acting of their own volition. Their true identity is unknown. The player can receive the Ball Guy's League Card outside of Motostoke Stadium after they become Champion. The Ball Guy mascot will also reward the player after defending their title in Wyndon Stadium.
This is a transcript of the back of the Ball Guy's League Card in Pokémon Sword and Shield.
- "This mysterious figure has taken it upon himself (herself?) to dress up in the fashion of the Pokémon League's official mascot. The mysterious individual is known to many as "the Ball Guy" but in point of fact, all are mystified when it comes to this person's true identity or age or even gender. While the Ball Guy is known for her (his?) habit of handing out rare Poké Balls here and there around Galar, it's a mystery as to why or even where these balls come from. It's all very mystifying..."
Champion Cup victories
Each time the player wins a Champion Cup tournament during the post-game, the Ball Guy will give them one of the following rewards.
As part of a campaign by the @poke_times twitter run by The Pokémon Company, the handle was taken over by the Ball Guy. During this time, the twitter posted this retweet campaign, promising rare Poké Balls if players retweeted it enough times. Eventually, all goals were met, and a set of nine total Poké Balls, including the Apricorn Balls, Dream Ball, and Beast Ball, were distributed via universal, region-free serial code. The distribution ended on January 15th, 2020.
In the anime
In Pokémon: Twilight Wings
In Assistant, an unmasked Ball Guy was seen sitting at a table in Wyndon.
In The Gathering of Stars, a Ball Guy was seen outside Wyndon Stadium.
In the manga
Shirudomiria's Ball Guy mask in Pokémon Adventures
In the Pokémon Adventures manga
Shirudomiria is a fan of Ball Guy. She owns a Ball Guy mask and was first seen using it to scare Marvin in PASS01.
The actual Ball Guy was first seen in Motostoke Stadium. They were seen reacting in pain when Kabu loudly congratulated Shirudomiria and Hop for beating the first three Galar Gyms.