She is a beautiful Oni alien who is capable of flying and generating electrical shocks and even lightning (resembling the thunder oni Raijin; one time Ataru dreamed of Lum wearing the same drums on her back as Raijin). She is extremely popular and is famous for ending her sentences with ~daccha (loosely translated as “yes?” or “you know?”). Except when in her schoolgirl uniform, human-style street clothes (consisting of jeans, sneakers, and a tee-shirt with a jacket), or a swimsuit, she usually wears her standard outfit consisting of a tiger-striped bikini and knee-high go-go boots (of which she has only one).
Lum is royalty and the daughter of the Oni alien Invader. She grew up on her homeworld Oniboshi.
When she was seventeen, the Oni attempted to invade the planet Earth, an event that would change her life forever. That day, Lum met Ataru Moroboshi for the first time. He had been randomly selected by computer to face her in a game of tag with the fate of the earth on the line. Ataru had been promised marriage by his then-girlfriend Shinobu if he could win, which spurred him to success, but upon catching Lum he declared "Now I can get married!" Lum misinterpreted this as a proposal to herself and accepted it. Because engagements are sacred on her planet, she is determined to be married to Ataru for the rest of her life. Since then, she has forced her way into his life as his "loving wife," much to his chagrin because it compromised his ability to flirt. The relationship between Lum and Ataru has been called "a humorously exaggerated parody of a common Japanese husband and wife dynamic."
While generally good-natured, sweet, faithful, and innocent, Lum also has a very hot temper. Her dream in life is to live in a "Sweet Home with Darling", in which she keeps house and raises the children, while Ataru, her "Darling", works a job. Unfortunately, this plan has some problems, such as how Lum's idea of "cooking" is to take very spicy ingredients likejalapenos, cayenne peppers, and Tabasco sauce and irradiate them with an alien energy bazooka until they carbonize into inedible, crystallized nuggets (although it doesn't seem to bother all non-earth-based life). As an alien she has access to many bizarre gadgets whose use she doesn't always understand completely, leading to comic results.