Lamù is the female protagonist of the anime Urusei Yatsura, an alien from the planet Oniboshi belonging to a race known as oni. She first arrives on Earth as part of an invasion attempt, but the planet’s fate is decided by a game of tag. The human selected to represent Earth is Ataru Moroboshi, and after he catches her, he shouts that he can now get married. Lamù misinterprets this as a proposal to herself and, because engagements are sacred on her planet, she considers herself his wife from that moment onward. She moves into his family home and calls him Darling, despite his constant attempts to chase other girls.

Lamù is depicted as a teenage girl with two small horns on her head, which are the source of her powers; her hair is iridescent in the original manga, while in the anime it is typically shown in shades of green and cyan. She wears a tiger‑striped bikini and matching boots as her usual outfit, though she also adopts school uniforms and other Earth clothing when attending Tomobiki High School alongside Ataru and his classmates.

Her personality is marked by a combination of innocence, impulsiveness, and fierce loyalty. She is openly affectionate and possessive of Ataru, often becoming intensely jealous when he flirts with other women. Her jealousy can trigger powerful electric discharges, which she also uses as a form of emotional expression. Despite her quick temper, she is generally cheerful, carefree, and trusting. She is naive about many Earth customs, which often leads to misunderstandings, but she is also highly intelligent when it comes to technology and can adapt or repair alien gadgets with ease. She struggles to cook food that humans can eat because her palate is accustomed to extremely spicy flavors, and her cooking is notorious among her Earth friends.

Lamù’s relationships are central to the story. Her bond with Ataru drives much of the series: she is devoted to him and believes he loves her deep down, even though he often runs away or cheats. She also cares for her young cousin Ten, who frequently causes trouble. Her childhood friends include Benten, Oyuki, and Ran; together they formed a rowdy group on their home planet. Lamù later becomes close to many of Ataru’s classmates, such as Shinobu, with whom she initially had a rivalry, and she is adored by a group of boys at school known as the Lum Fan Club, though she never returns their romantic interest.

Over the course of the story, Lamù evolves from a more aggressive and mischievous guest character into a more settled and compassionate presence. Her early fiery and confrontational traits gradually soften, and she takes on a role that is more emotionally mature, often mediating between Ataru and others. She remains consistently loyal to Ataru and deeply invested in their relationship, even when he tests her patience.

Lamù’s notable abilities include flight and the capacity to generate high‑voltage electricity from her fingers or hands. These powers are tied to her horns; if the horns are removed or bound with special ribbons, she loses her supernatural strength, flight, and electrical control. She is also highly resistant to cold and can withstand temperatures that would trouble ordinary humans. She owns a small tiger‑striped UFO that hovers above Earth and serves as her personal spacecraft, and she often carries advanced alien technology stored in her bikini top. Aside from her electrical attacks, she has no superhuman physical strength and relies on her wits and gadgets to solve problems.