Bill is the talented and famous inventor. He invented the original Pokémon storage system and Time Capsule.
People, including himself, call him a Pokémaniac because of his large collection of both common and rare Pokémon. The first one he caught was an Abra; however, his favorite Pokémon are Eevee and its evolutions. Bill also gives a free Eevee to Ethan/Kris/Lyra in Generation II and its remakes and another one to Bebe in Generation IV, which is later given to Lucas/Dawn.
Bill also has several friends that share his interests in computer technology. One of them is Celio, his old friend from One Island in the Sevii Islands. He is also close with Lanette and Bebe, the storage system developers of Hoenn and Sinnoh, respectively.
Bill also has some fans, like PokéManiac Brent of Generation II who calls the player with information about him. Most of his calls are trivia about Bill himself and his family, such as the fact that Bill's mother used to be a Kimono Girl and that Bill's younger sister can't wink. Brent also revealed the fact that Bill is lactose-intolerant, which was also stated by Celio in Generation III.
Bill has been shown to have a large family. In Fuchsia City lives his adult sister and grandpa, who in Generation II watches over Bill's cottage on Route 25 while he is visiting the rest of his family in Goldenrod City.
In the Japanese versions of the games, Bill speaks in Kansai Dialect like most Goldenrod City natives.
I understand with love comes pain, but why did I have to love so much?