Asa is Yuru's younger twin. Of the twins separated by day and night, she is the "day" twin so she is destined to have the power of Kai. She is the master of Yin and Yang: Ohagi and Daifuku.

Asa is a resilient and determined individual who has been through a lot of trauma in her life. Despite this, she remains caring and protective towards those she considers family, particularly her brother Yuru, she has one a big sister vibe, even though she is technically her brother's ''little sister''.

Asa and her brother Yuru are a synchronized duo, despite the instances. They who share wild beliefs, including their stance that every child should carry weapons with them, being considered ''clueless siblings''. Both Asa and Yuru are strong-willed mind individuals who fiercely protect what they believe in. Asa tends to take on a protection him role in her relationship with her big brother's security being your priority. Initially taken aback and shocked by Asa's masculine personality, Yuru has since grown accustomed to her ways and they now work together seamlessly.

Despite outward appearances, Asa's cool façade crumbles into a puddle of tears and exaggerated gestures when emotions run high around on Yuru. Asa turns into a comical and emotional character whenever Yuru is around, discovering something new, as if watching a newborn explore the world. Although Asa appears serious and composed to strangers, she may be entertaining silly thoughts and ideas in her mind

Asa also has a deep-seated fear of being alone due to her past experiences. She is fiercely loyal and will go to great lengths to seek revenge against those she believes have wronged her and her family. Asa is also a gifted and powerful individual with supernatural abilities that she has honed through her own strength and determination. She can be impulsive at times, but is also strategic and calculating when necessary. Although she can be wasting, Asa ultimately values honesty and sincerity in her relationships. Her experiences have made her deeply introspective and reflective, and she is constantly seeking to understand herself and her place in the world.