Karane Inda is one of the first two girlfriends of Rentarou Aijou, introduced alongside her best friend, Hakari Hanazono, as a first-year student at Ohananomitsu High School. She is a sixteen-year-old girl with a birthday on September 9th. Physically, Karane has orange-blonde hair typically styled into twin tails and hazel eyes, with her school uniform consisting of a brown sweater over a white dress shirt, a short skirt, and loose knee-high socks. She is noted to be quite beautiful, to the point where she is sometimes approached by other boys, much to her own annoyance and Rentarou's jealousy.

The defining aspect of Karane's personality is that she is a quintessential tsundere. She is generally a straightforward and honest person, but she is utterly incapable of expressing two specific things: her deep love for Rentarou and her insecurities regarding her perceived lack of a feminine figure. Her desperate attempts to mask these feelings cause her to say the opposite of what she means, often lashing out with violent outbursts and declarations of "It's not like I did it for you or anything," a phrase her name alludes to. This behavior makes her the primary source of physical comedy and the straight man, or tsukkomi, of the group, as she is constantly forced to call out and react to the absurd antics of Rentarou and the other girlfriends. Despite her prickly exterior, she is incredibly kind and caring underneath, and while she hates her own inability to be honest, it is an inherent part of who she is, as her entire family are tsunderes as well.

Karane and Hakari are introduced as fated soulmates simultaneously when they both bump into Rentarou on his first day of high school and fall in love with him at first sight. When they both confess, Rentarou resolves to date them both at the same time, to which Karane reluctantly agrees, marking the foundation of the Rentarou Family. While she and Hakari are best friends, they are also rivals for Rentarou's affection and are frequently seen arguing. However, their relationship is uniquely intimate, as they often find themselves in compromising situations, including sharing many kisses with each other, some accidental and some deliberate, creating a deep bond that transcends simple friendship. With Rentarou, Karane's affection is expressed through her actions rather than her words, as she is often moved to tears by his kindness and is fiercely protective of him. Rentarou, for his part, completely understands and adores her tsundere nature, even declaring that he loves her punches because they are a manifestation of her passion and vitality.

Karane's role in the story is central as one of the original two girlfriends, and her development frequently revolves around her struggle with her own personality. A significant arc involves her deep-seated fear that her tsundere tendencies will drive Rentarou and the others away, a manifestation of her low self-esteem. This insecurity leads her to take a drug that removes her tsundere nature, making her overly nice and compliant. But the family, led by Rentarou, quickly realizes that they miss the "real" Karane, and they work to restore her original personality after Rentarou passionately reaffirms that he fell in love with her specifically because she is a tsundere. This storyline reinforces that her personality is not a flaw to be corrected but a core part of her identity that is loved and accepted.

In terms of abilities, Karane is exceptionally strong, currently considered the physically strongest of all of Rentarou's girlfriends. Her raw power allows her to go toe-to-toe with the leader of the Gorira Alliance and perform feats of strength like the "Karane Catapult," hurling another girlfriend through the air, or the "Extinction Meteor" technique during a baseball game. Despite her aggressive tendencies, she is also academically gifted, consistently ranking above average and even placing just ahead of Rentarou in their class rankings.