Hilbert is a tall, thin boy. He has medium length, messy mud brown hair and brown eyes. He wears a black T-shirt underneath a sky blue jacket that has a sea blue neck and cuffs and a white zip with gray, slightly baggy pants tightened by a black belt with a silver metal buckle. He also wears a scarlet red cap that has a black Poké Ball logo, a scarlet red pair of shoes with black panels and white soles, and on his left wrist he wears a blue Xtransceiver. He carries a black and blue messenger bag with a large white Poké Ball in the center.
Like other protagonists, Hilbert is a quiet person.
Black and White
Not much is known about his past before the events of Pokémon Black and White. When he was a younger child his father ran out on them to pursue his dream in becoming a Pokémon Master. While fighting Team Plasma, One of the grunts says "Hey kid you look like smaller version of my friend. Are you related to him?" and if you lose the battle, the grunt will say before you black out "You're even as weak as him!" Another reference while talking to Bianca is how they played hide and go seek a lot as little kids and Cheren saying he is too old for that.
Black 2 and White 2
This character is mentioned many times in this game, but there is only little information on his location. Sometime after the events of Pokémon Black and White, N came back and Hilbert went to another region (Most likely Johto) to stop him from doing any more harm to another region. The reason why he most likely Johto is because there was a reference saying that he "Disappeared by the ghost towers" The burned tower in Johto is often referred to as the Ghost tower in Pokémon Crystal. It is the tower where the legendary dogs were found. Entei, Raikou, and Suicune. In Pokémon Black and White, an old lady said he was an extremely well legendary Pokémon catcher which most likely means he went to another region to find N but instead got distracted in finding the other regions legendary Pokémon.
- Main article: Hilbert's Battle Subway Pokémon
- Ash Ketchum's attire in Unova seems to be based on Hilbert's clothes.
- At the Pokémon Black & White Tour in the Pokémon Black & White demos he was referred as "Blair".
- Before the release of the games, he was also referred to as simply "Black".
- Even though he and his counterpart Hilda do not appear in the sequel of Black and White, they are mentioned by several characters in the game that met them in the first part of the game.
- Hilbert's mother and Nate/Rosa's mother knew each other since childhood. It is also known that Hilbert/Hilda's mother was a Pokémon Trainer and Rosa/Nate's mother was a Pokémon nurse that worked at a Pokémon Center.
- The whereabouts of his father are not told in-game, but he is said to be a Pokémon Trainer on a journey, similar to Ash's father.
- According to Junichi Masuda during a fan meeting, Hilbert, Hilda, Bianca and Cheren are 14 years old in Black and White.