Jong-In Choi, also known as Shin Mogami, is an S-rank Hunter who serves as the guild master of the largest Hunter guild in Korea. He is a master fire mage capable of summoning devastatingly large fire attacks, showcasing his immense magical power. As the leader of the most prominent guild, he holds significant influence and authority within the Hunter community, making him a major figure in the world of Hunter politics and high-rank raids.

In terms of personality, Choi Jong-In presents a composed and somewhat polished exterior, though he is prone to moments of theatrical pettiness. When Sung Jinwoo, newly re-evaluated as an S-rank, ignores his attempt at conversation, Choi reacts with playful indignation, asking an official present whether he had been impolite. This suggests that beneath his refined demeanor, he has a noticeable ego and expects a certain level of recognition. His immediate approach to meet the newest S-rank shows that he is proactive and likely interested in recruiting or building alliances with powerful individuals.

His role in the story begins when he arrives at the Hunter reassessment center along with other high-ranking figures like Go Gunhee to witness the emergence of Korea's tenth S-rank Hunter. He attempts to engage Jinwoo in dialogue, but is rebuffed without explanation, leaving him somewhat bemused. The character has a key working relationship with Cha Hae-in, another S-rank Hunter who acts as his second-in-command. While his personal motivations are not deeply explored in his early appearances, his actions are driven by his responsibility to manage the largest guild and his strategic interest in powerful Hunters. There is little immediate development shown, but his introduction marks the expansion of the story's world as Jinwoo begins to interact with the elite upper echelon of Hunters.