Wilt

Wilt is generally quite accommodating, although he has a sense of self-worth and is able to stand up for himself despite certain limitations.
He once refused to help Blue after discovering him mocking tall people. Although Wilt is sweet and kind at heart, he does have a dark side, as he once did. When Blue returns to the bus, bragging about how he pulled off the latest prank, he ends up sitting on a whoopee cushion. Blue realizes that Coco couldn't have pulled this prank, as she got on the bus after him. Blue demands to know who put the whoopee cushion on his seat, and Wilt ends up smiling, implying that he pulled the final prank.

Always apologizes even when he is not at fault

Fear of disappointing loved ones (guilt complex): This fear developed after his injury in a basketball game, when he defended his creator, Jordan, but because of it, they lost the game. For many years, Wilt suffered from burning shame and a fear of looking his creator in the eye, believing he had let him down.

Fear of being rude (people-pleaser syndrome): Wilt is terrified of refusing to help someone or causing them inconvenience. Because of this, he apologizes pathologically (even when he's innocent) and allows others to take advantage of his kindness.

Madam Foster is a tiny, energetic, and incredibly kind elderly woman who founded Foster's Home. Unlike the prim Mr. Herriman, she loves fun and mischief, has a great sense of humor, and is incredibly fond of all imaginary friends. Wilt treats Madam Foster with the deepest respect, devotion, and warmth. He appreciates her for creating this safe place for everyone without a home and is always ready to protect her.

Frankie is Madam Foster's 22-year-old red-haired granddaughter. She does all the heavy lifting around the house: cooking, cleaning, laundry, and chauffeuring her friends around on the bus. Frankie is often tired and frustrated by Mr. Herriman's strict demands. Wilt is her main and most reliable assistant. He genuinely pities Frankie, always volunteers to help her with cleaning and cooking, encourages her, and apologizes when he thinks her imaginary friends are too much of a hassle.

Coco is a crazy hybrid of a bird, an airplane, and a palm tree. She can't speak human language and only says one word: "Coco!" with varying intonations. Despite this, she is very smart and resourceful, and even lays plastic eggs containing useful (or strange) objects. Wilt understands Coco's "language" perfectly, always translating her phrases for others, and treats her eccentricities with respect and warmth.

Eduardo is a huge, hairy purple monster with enormous horns and a menacing appearance, but with the heart of a little child. He is incredibly timid, afraid of the dark and noises, often cries and seeks protection. Wilt is Eduardo's best friend. Wilt always treats him with great tenderness, affectionately calling him "Ed," protecting him from fears, comforting him when he cries, and helping him feel brave.

Wilt was created by a boy named Jordan, who loved basketball. Wilt lost his left arm and injured his eye during a crucial basketball game against his cruel imaginary friend, Fowles, while defending Jordan. Wilt felt guilty about this loss, retreated to Foster Home, and has been obsessed with helping others ever since. He treasures the memories of Jordan.

Mr. Herriman is a stern, prim, elderly imaginary rabbit in a tailcoat and monocle. He is the general manager of Foster's House and demands perfect discipline. Wilt deeply respects Mr. Herriman, obeys him unquestioningly, and is terrified of disappointing him or being reprimanded.

Blue is Mack's best friend, a selfish, arrogant, boastful, and hyperactive blue, teardrop-shaped imaginary friend. Blue constantly gets everyone into trouble and often shamelessly takes advantage of Wilt's willingness to help. Despite Blue's whims, Wilt is endlessly patient with him, forgiving of any antics, and always ready to help.

Foster's House is a huge, colorful Victorian mansion, home to hundreds of imaginary friends who have lost their owners. It has strict house rules, enforced by Mr. Herriman. Wilt truly loves the house, considers it his sanctuary, and constantly helps out with the housework: cleaning, fixing things, and caring for the newcomers.

Wilt is an unusually tall imaginary friend, standing over 2.5 meters tall. His entire body is covered in smooth red skin. A large blue number "1" is painted directly across the center of his chest, resembling a basketball jersey, but he wears no clothing other than shoes. Due to an old sports injury, most of his left arm is missing—only a short, neat stump remains. His right arm, by contrast, is incredibly long and thin, with suction cups on the fingertips. Wilt's left eye is slightly crooked and droops, and small scars are visible on his face. He wears classic white basketball sneakers that squeak loudly with every step, and a wide blue, white, and red wristband is worn on his right arm.

Wilt has an incredibly kind, gentle, and altruistic nature. He's polite to a fault and feels an overwhelming need to constantly apologize to everyone, even when he's innocent (his favorite phrases are: "Oh, sorry!", "Am I interrupting?", "Is it okay?"). He has a pathological inability to say "no," which often leads others to exploit his steadfastness. Wilt is an inveterate optimist, always trying to see the good in people and situations. He loves basketball, teamwork, and honesty, is genuinely loyal to his friends, and is willing to sacrifice his own comfort to help anyone. He is completely devoid of egoism, aggression, or pride, and is always encouraging and caring.