Age: 16
Birthday: March 14th (Pisces)

A first year student at Ohananomitsu High School, an alumnus of Mirei Middle School, and Aijou Rentarou's fourth girlfriend. She is focused on being practical and efficient with everything she does, to the point where she disregards the "useless" emotions of herself and others. Due to this, she comes off as unfeeling or uncaring to others.

Nano is the smartest among the girls. In her school exam, she gets the perfect score (700/700), which is better than the scores of genius-level characters in other manga. Nano has memorized hundreds of digits of Pi, which she sometimes uses to calm herself down. Due to her extreme intelligence and efficiency, in most difficult situations Nano is the first to come up with solutions. However, her solutions are sometimes brutal due to her lack of social experience.

Due to her extreme intelligence and efficiency, Nano has much information like a walking encyclopedia.

Nano has acrophobia; a fear of heights.

She also has proficiency in hand-to-hand combat and melee weapons, particularly boxcutters.

Name/Birthday Pun Explanation:

Eiai means "flourish, prosperity, honor, glory, splendor" (栄) (ei) and "meeting, tryst, date, rendezvous" (逢) (ai).

Nano means "calm, lull" (凪) (na) and "from" (乃) (no).

Eiai being pronounced as “A.I.” (Artificial Intelligence), and Nano reference to Nanotechnology because of her personality.

Nano's birthday is on March 14, a reference to the constant number of pi (π ≈ 3.14).

(Source: 100Kanojo Wiki)