Ayumi grew up as the youngest sibling in the Otosaka family, living with Yuu after their parents passed away. She has no recollection of Shunsuke, her eldest brother, due to his time-traveling ability, which altered their past.

As a middle school student, Ayumi idolizes Yusa Nishimori, often quoting her catchphrases like “Isn’t it the best~?” with great enthusiasm. She enjoys cooking (albeit poorly) and often prepares meals overloaded with pizza sauce, much to Yuu’s dismay.

Initially, Ayumi appears to be an ordinary girl, but she inherits a supernatural ability like her brothers, which emerges in a catastrophic way and becomes a turning point in Yuu’s character development.

Ayumi has short, light brown hair styled with a pink ribbon, bright golden-brown eyes, and a petite frame. Her youthful and innocent appearance reflects her bubbly and affectionate personality.

She is most often seen wearing her middle school uniform, consisting of a white blouse, a red ribbon tie, and a pleated navy skirt. At home, she wears casual dresses or sweaters, often helping around the house with a lively demeanor.

Ayumi is cheerful, affectionate, and somewhat childish, frequently clinging to Yuu and playfully annoying him with her excessive doting. She is optimistic and carefree, often giggling and excitedly praising things she enjoys, such as Yusa Nishimori and food.

Despite her playful nature, Ayumi is also kind and caring, showing genuine concern for Yuu’s well-being. She worries about him skipping meals or overworking himself, often preparing questionable but well-intentioned meals for him.

Though she appears innocent and naive, she later proves to have a hidden strength, particularly when dealing with emotional pain and loss.

• The Emergence of Her Ability
  Ayumi’s life takes a tragic turn when she awakens her supernatural ability, Collapse, which allows her to instantly destroy everything around her. However, she is unaware of this power until it activates uncontrollably in her school, causing massive destruction. During this event, Ayumi accidentally causes a building to collapse, leading to her apparent death, which becomes one of the most traumatic moments in Yuu’s life.

• Yuu’s Descent into Despair
  Ayumi’s death devastates Yuu, causing him to spiral into deep depression and isolation. He abandons his responsibilities, engaging in reckless behavior, until Nao Tomori helps him recover from his grief.

• Saved by Time Travel
  Fortunately, due to Shunsuke’s time-traveling abilities, Yuu is able to go back in time and prevent her death by stealing her ability before it activates again. This event marks Yuu’s growth, as he finally learns to use his powers for good rather than selfish gain.

• Life After Her Rescue
  After being saved, Ayumi returns to her normal cheerful self, though she is grateful to her brothers for protecting her. She continues living with Yuu, blissfully unaware of the pain and sacrifices he endured to save her.