Saika Totsuka is known for his gentle, kind-hearted nature and soft-spoken behavior. His delicate features and graceful mannerisms often lead others especially Hachiman Hikigaya to momentarily forget that he is male. Due to his feminine appearance, many girls at Sōbu High refer to him as the school’s “prince.” Despite the frequent misunderstandings surrounding his gender, Saika earnestly strives to present himself in a more traditionally masculine way and becomes visibly uncomfortable when mistaken for a girl.

Saika is friendly and compassionate, easily getting along with others and avoiding conflict whenever possible. He is modest and easily flustered, often seen blushing particularly in interactions with Hachiman, who is frequently bewildered by Saika’s charm. His warm personality and supportive attitude make him a beloved figure among his peers, especially within the Tennis Club, where his presence often motivates others to perform at their best.

Saika Totsuka possesses a delicate and feminine appearance that often causes others to mistake him for a girl. His short silver-gray hair, large sparkling blue eyes, and fair complexion contribute to his androgynous charm. This has led to frequent moments where even Hachiman Hikigaya forgets that Saika is actually male. Despite his gentle looks, Saika makes an effort to present himself in a more traditionally masculine way.

Throughout most of the series, Saika is seen in his gym uniform, often accompanied by his tennis racket or a towel draped around his neck befitting his role as the Tennis Club president. In the anime, his outfit includes a dark and light green sports jacket, similarly colored shorts, black knee-length tights, and a long-sleeved, light green V-neck shirt. In the manga, his shorts appear slightly longer and the tights are not visible. In the light novel illustrations, his outfit initially features a light blue jacket, which later changes to green, and he wears a short-sleeved white undershirt with a blue collar. He also consistently wears a black bracelet on his right wrist as part of his look.

Saika Totsuka is highly athletic, with a strong passion for sports particularly tennis. As the captain of the Tennis Club at Sōbu High School, he demonstrates excellent leadership skills, which are notably recognized by Hachiman Hikigaya. His ability to motivate and encourage others, often unintentionally through his natural charm and “cuteness,” was showcased during the school’s Athletic Festival, where he served as the captain of the red team in the Bo-Taoshi event.

In addition to his athletic capabilities, Saika has shown unexpected talent in acting. During the Cultural Festival, he took on a role in Hina’s yaoi-themed class play, delivering a convincing performance that impressed both classmates and the audience.

Saika’s perceptiveness is also notable. In episode 11 of season 2, he demonstrates emotional intelligence and observational skill by picking up on Hachiman’s inner stress and struggles, showing that he is not only a capable athlete and leader but also empathetic and attentive to those around him.

Saika Totsuka is affectionately called “Sai-chan” by Yui Yuigahama, reflecting her friendly and informal way of speaking. Due to his graceful appearance and gentle personality, many of his female classmates refer to him as “The Prince,” a nickname that highlights his popularity and charming presence, despite the frequent confusion about his gender.