TV-Series
Description
Eru Aharen serves as the younger sister to Reina Aharen and the older sister to Ren Aharen, positioning her as the middle child. She bears a striking resemblance to Reina, sharing long silver hair and deep blue eyes, but distinguishes herself through her taller height and more developed physique, lending her a more mature appearance despite being Reina's junior. Her distinctively sharp snake-like eyes further enhance this mature impression and set her apart.

Eru presents herself as a classic tsundere, often projecting a cold, strict, or confrontational front, particularly towards Shōta Raidō, whom she initially distrusts due to her protective instincts regarding Reina. Beneath this tough exterior, she holds deep affection for her family, especially Reina. She routinely performs secret acts of kindness, like cooking for Reina during illness or spending her own money to win prizes for loved ones. Struggling to express her true feelings openly, she habitually supports her family from the shadows without seeking recognition. A self-imposed sense of responsibility drives her to take on burdens beyond her years, sometimes overextending herself to meet perceived expectations, such as secretly learning skateboarding after neighborhood children mistake her for Reina and request lessons.

Her relationship with Reina forms her core motivation. Eru deeply admires her older sister and remains highly protective, manifesting as wariness towards Raidō as he grows closer to Reina, occasionally leading to confrontations. Over time, she gradually softens towards Raidō upon observing his consistent kindness. She also shares a close, protective bond with her younger brother, Ren. Beyond her family, Eru attends the same junior high school as Raidō's younger sister. Initially distant, bonding over their mutual sibling connections eventually fosters a genuine friendship, expanding Eru's social circle.

Eru first appears in the anime during Raidō and Reina's first year of high school, while her manga debut occurs later, during their second year; at that time, she is a second-year junior high student. Her background emphasizes her role within the Aharen family dynamics, where her parents' busy work schedules often compel her to act as the primary support for her siblings, reinforcing her serious demeanor and desire to appear reliable. A notable anecdote involves her school swimsuit, used in her final elementary year and later given to Reina for high school, bearing the label "6-3 Aharen."

Throughout the series, Eru undergoes subtle development. Her initial hostility towards Raidō diminishes as she witnesses his genuine care. Her friendship with Raidō's sister also encourages her to become more open in interactions. While remaining reserved, she learns to express her feelings more directly, especially concerning her siblings, such as during family activities like bathing with Reina where her affectionate yet shy side surfaces. Her unique speech patterns and catchphrase "desushi" further define her character.