Kurumi Kasuga is one of the two younger twin sisters of Kyōsuke Kasuga, the protagonist of Kimagure Orange Road. She and her family are espers who must conceal their supernatural abilities from the public to avoid exploitation, a condition that has forced the Kasuga household to relocate multiple times after incidents involving their powers. Kurumi’s own accidental use of her abilities to enhance her sprinting during a track event was the reason for the family’s most recent move at the start of the series. She is the more energetic, tomboyish, and mischievous twin in contrast to her reserved sister Manami. Her personality is defined by a restless, childlike curiosity and a playful streak that frequently overrides the family’s need for secrecy. She can come across as bratty or spiteful in her pranks, but is ultimately a good-natured girl who cares about those around her. Kurumi’s motivation is rarely complicated; she seeks excitement, fun, and the freedom to use her psychic talents whenever an opportunity arises, often without fully weighing the consequences. This impulsiveness makes her the chief troublemaker of the household.

In the story, Kurumi acts as a supporting source of comedy and chaos. She frequently uses her powers to play tricks, help her friends, or meddle in her brother’s affairs, inadvertently creating situations that complicate the central love triangle. Her role leans toward lighthearted interference rather than driving dramatic conflict, though her actions often serve to remind the family of the constant danger of being discovered. Kurumi is a vocal and enthusiastic supporter of Hikaru Hiyama in Kyōsuke’s romantic dilemma, even styling herself a founding member of “Team Hikaru,” which places her squarely in the middle of the series’ relationship tensions. Her key relationships center on her immediate family. With Kyōsuke, she shares a typical sibling dynamic of teasing and annoyance tempered by loyalty. She and Manami are polar opposites in temperament but share a close twin bond, often working together when mischief is afoot even if Manami is the more cautious of the pair.

Development for Kurumi is subtle across the series. She does not undergo a dramatic transformation; instead, she remains a consistent, high-spirited presence whose antics occasionally highlight the limits of her impulsiveness. As events unfold, there are glimpses of growing awareness about the seriousness of hiding her family’s secret, but her core personality stays intact. Her loyalty to friends and family is steadfast, and she matures just enough to occasionally temper her recklessness.

As an esper, Kurumi possesses a range of psychic abilities common to the Kasuga bloodline. She can perform telekinesis, moving objects with her mind, and has demonstrated the capacity to temporarily boost her physical speed and strength beyond normal human limits. Like all family members, she must keep these powers hidden, yet she habitually uses them in daily life—levitating snacks, tripping up unsuspecting classmates, or staging supernatural pranks that generate much of the story’s lighter moments. Her command over these abilities is innate and instinctive rather than trained, which contributes to the unpredictable outcomes that often force the family to cover their tracks.