Yuuta Asaba is the older identical twin brother of Yuuki Asaba, identifiable by his center-parted yellow/blonde hair and height of 174.8 cm. Born on June 20 under the Gemini sign, he shares ochre eyes with his brother and wears the winter school uniform with an open blazer. A small mole on his lower right hip provides another distinguishing mark.

More independent and emotionally expressive than Yuuki despite their shared reserved monotone, Yuuta acts as the most mature and observant in his friend circle. He detects unspoken sentiments like Yuuki's interest in cafeteria worker Kayo or Shun Matsuoka's future anxieties. Protective of close friends—especially Shun and Yuuki—he joins Yuuki in teasing Kaname Tsukahara but respects his brother's autonomy by never deciding for him.

Academically strong and athletically skilled, Yuuta excels in studies, sports, and drawing—a talent nurtured through Yuuki's manga enthusiasm. He considers his brother his primary vulnerability, offering subtle support without intrusion. He prefers warm udon and quiet settings while disliking celery.

During his second year in Class 2-4 with Shun and third year in Class 3-1 alongside Kaname, Yuuta participates in the tea ceremony club with Shun. He previously practiced kendo in middle school, demonstrating notable prowess. Though more popular with girls than Yuuki in elementary school, both attract attention in high school.

Romantically, Yuuta dates Takahashi in their third year, dancing together at the sports festival and exchanging Valentine's chocolates. Their relationship ends when Takahashi initiates a breakup, misreading his reciprocating feelings as one-sided. This thread resurfaces when she later offers him chocolates again.

Yuuta maintains childhood friendships with Shun, Kaname, and Yuuki since kindergarten. His bond with Yuuki features mutual reliance, seen when Yuuki rests on his shoulder during walks or borrows his exam notes. While openly aspiring to visit Paris, he privately favors staying in Japan for hot springs.