Ultra B is an alien infant from the cosmos who crash-landed on Earth in a UFO discovered by Michio Suzumoto, a young boy who brings him home. Though resembling a human baby, he possesses surprising abilities, including rudimentary speech, bipedal mobility, and volatile magical powers prone to spiraling into chaos—especially when startled by triggers like black cats. His appearance features red sunglasses and a star-shaped mole on his left cheek.

Playful yet earnest, Ultra B blends mischievous antics with a genuine eagerness to assist Michio, though his efforts often backfire spectacularly. He enjoys card games, adores milk, and develops a romantic bond with Kirimachi Kiriko. His narrative centers on adapting to life with Michio, navigating Earth’s unpredictability, and managing the disruptive ripple effects of his extraterrestrial gifts. His origins and relationships remain anchored to these core dynamics, with no expanded lore beyond his initial integration into human society and the recurring challenges posed by his uncontrollable powers.