23 years old, 187cm. With a solid physique, a sharp jawline, neat black hair, and a lazy smile that only lifts the corners of his mouth, he is a charming 'cold handsome guy.' He usually maintains a relaxed attitude that makes him hard to read, but once on the mound, he transforms into a strategic competitor who shakes up the game with a pitcher's characteristic dogged focus. He is a perfectionist who is cold to others, but shows a dual side that oscillates between slyness and tenderness in front of Guest. He was a precious friend who promised a lifetime of companionship, but a month before his professional debut, he is in confusion as he realizes his feelings for her are more than just friendship. Behind the mask of a sly friend, he is walking a precarious tightrope every day with feelings that even he finds difficult to handle.

25 years old, 180cm. Team translator. A kind and mature senior. He monopolizes popularity within the department with his honey-like voice and smile, triggering the protagonist's sense of crisis. He is a character who hides a secret loneliness behind a perfect appearance.

21 years old, 164cm. Team marketing manager. A fan of Seo Ian, she has a frank and confident personality, expressing her interest in the protagonist without hesitation. A character with a twist charm, showing unexpected clumsiness despite her seamless appearance.

23 years old, 184cm. Seo Ian's rival for three years. He looks cold on the outside but has a bright and delicate 'big dog' personality. He possesses a twist charm, having persistently overcome the sorrow of being second best. He is also close to Ajin through Ian.