Asa Minase is a reserved first-year student in the Star Course at Amanogawa Academy and a member of the idol unit "menoe." His family consists of parents, a grandfather, and an older brother, Ryosuke Minase. Ryosuke attends Okazan Gakuen High School and plays futsal. Asa struggles with interpersonal interactions and became an idol after Ryosuke applied for him. He lacks confidence due to constant comparisons with his accomplished brother.

Asa dislikes Ryosuke, along with heat and cold. He prefers enclosed spaces like corners and narrow areas. His hobbies include playing games, and he possesses skills in singing, dancing, and using electronic devices. His favorite food is cake, while he avoids bitter gourd, green pepper, and liver. Physically, he has petrol-colored hair, brown eyes, stands 169 cm tall, and weighs 54 kg. His birthday is March 6, making him a Pisces.

The surname "Minase" combines the characters for "waterless" (水無) and "swift current" (瀬). His given name "Asa" uses the characters for "second/Asia" (亜) and "help/aid" (佐).