Yeong-Gi Hirahara, commonly known as Yeong-Gi, is the second son to Randulph Skuli Hirahara. His immediate family members called him by nickname - Nol. He is currently enrolled as a student in Nongke Math and Science Academy (NMSA) and is working in Hirahara Corporation, his father's company.

Yeong-Gi has a bright personality and is often chipper. He is seen as a very friendly, approachable person. Unlike Kousuke, Yeong-Gi displays his happier emotions more openly. He is also very persistent as shown in the beginning of his relationship with Shin-Ae. Yeong-Gi is very observant and quick, similar to Kousuke, as they both perceive situations and people's intentions. Yeong-Gi treats people equally no matter what path of life they walk. He is a man who keeps his promises, often saying "you have my word" and fulfilling it afterward. His kind personality can be easily misunderstood or taken for granted, which has taken its turn for him. Initially and even later on-his actions are proved sincerely when Kousuke explained its his natural demeanor. However, when his anger is triggered, Yeong-Gi acts quite aggressively and headstrong, directing his anger to his punching bag rather than expressing those negative emotions verbally. It has been hinted that he has been struggling to contain his internal pain and conflict. On a couple of occasions, his seething pain has vented out in his thoughts and towards Kousuke.