Arumi Asahina is the female protagonist of the story, a twelve-year-old girl in the sixth grade who was born and raised in the Abenobashi shopping arcade in Osaka. She is portrayed as a very mature and pragmatic young woman, especially when compared to her best friend, Sasshi. Acting as the sensible and rational counterweight to his oddball and often perverted antics, she has a strong personality and a fiery temperament that makes her the more dominant and influential member of their pair. Her personal motto, which she often repeats, is that being human and having one's health are the most important things.

Arumi's primary motivation at the beginning of the story is rooted in a significant life change. Her family, which runs a French restaurant in the arcade called the Grill Pelican, is preparing to close the business due to redevelopment plans in the area. This forces the family to move to Hokkaido, a prospect that Arumi accepts with a degree of maturity, even as it means leaving her childhood home and her best friend Sasshi behind. Her grandfather, Masayuki Asahina, a stubborn man who founded the restaurant, is initially defiant against the move, but an accident that shatters the restaurant's pelican statue, a magical guardian of the district, triggers the series of surreal events that follow.

In the story, Arumi is not a passive participant. She and Sasshi are thrust together into a series of bizarre parallel universes, each a warped parody of a different genre like role-playing games, science fiction, or martial arts films. Her role is often to provide a grounding, level-headed perspective in these chaotic worlds, acting as a foil to Sasshi's more excitable and genre-savvy, yet often clueless, behavior. Unlike Sasshi, who is frequently the victim of slapstick misfortune, Arumi tends to land on her feet and is often seen keeping Sasshi in line by smacking him with a paper fan. She is also shown to be resourceful, such as when she cleverly purchases a protective amulet that proves to be the key to defeating an enemy in the first parallel world they visit.

The core of the narrative revolves around Arumi's key relationship with her best friend, Sasshi Imamiya. Their dynamic is the emotional heart of the series, and their journey through the dimensions forces them to confront their feelings about the impending end of their childhood and their separation. While Arumi generally maintains her composure, the different worlds they visit often reflect personal anxieties and unresolved emotions, with one episode even casting her as the antagonist goblin of a dating-sim world, much to her frustration. Her other important relationships are with her family members, particularly her eccentric father and her grandfather, who appear as different characters in the parallel worlds.

Throughout the series, Arumi undergoes significant development. Initially focused on the practical reality of her family's move, the journey through the surreal dimensions forces her to confront deeper emotional truths about change, growing up, and what she truly wants. The series explores the idea that the parallel worlds are tied to her own and Sasshi's unresolved feelings, and her arc culminates in a personal resolution about accepting change while holding onto what is truly important. Despite the fantastical settings, Arumi herself does not possess any overt magical powers; she is not a magical girl or a magical girlfriend. Her strength lies in her common sense, her strong will, and her ability to navigate the absurdity around her with a level head. Her family also holds one of the four magical insignias of the Abenobashi district, which is the symbol of the pelican.