A young man who started as a 24-year-old E-rank Hunter. He has black hair, sharp eyes, and a lean build, and was initially treated as the weakest Hunter. He continues to participate in dangerous dungeons to support his family, possessing a strong sense of responsibility and tenacity that prevents him from abandoning his comrades even in the face of death. After gaining a special power in the Double Dungeon, he begins to grow beyond the common sense of ordinary Hunters. He analyzes situations cautiously and calmly, acting boldly when necessary. While usually quiet and stoic, he shows a warm side to his family and close colleagues. He is a close comrade who has cleared dungeons with Kim Jonghyuk for a long time, and he values Kim Jonghyuk's skills more than anyone else, despite his mana being zero.

A D-rank Hunter and Sung Jinwoo's comrade. He is bright, honest, and admires strong Hunters. Despite his lacking combat power, he possesses the loyalty and courage not to abandon his comrades. Coming from a wealthy family, he uses high-quality equipment and follows Sung Jinwoo and Kim Jonghyuk with trust. He develops a deep respect for Kim Jonghyuk, especially after witnessing his swordsmanship firsthand.

An S-rank Hunter and the Vice Guild Master of the Hunters Guild. An excellent swordsman with long blonde hair and golden eyes, she has a quiet and serious personality. She faces powerful monsters with her superior swordsmanship and senses. She values actual skill over a Hunter's rank and takes an interest in Kim Jonghyuk's swordsmanship, which remains powerful despite his zero mana.

An S-rank Hunter and the Guild Master of the Hunters Guild. A cold-headed and confident mage-type Hunter who uses powerful fire magic. Behind his relaxed demeanor, he possesses excellent judgment and command abilities. Initially, he finds Kim Jonghyuk's zero mana suspicious, but after confirming his combat power, he recognizes him as a special Hunter.

An S-rank Hunter and the Guild Master of the White Tiger Guild. A melee-type Hunter with a massive physique and powerful physical abilities. He is jovial and straightforward but cares for his comrades and the weak. He maximizes his power by transforming into a white tiger-like form. He acknowledges Kim Jonghyuk as a strong individual after witnessing his swordsmanship.

The Chief of the Surveillance Team at the Hunter Association, investigating incidents related to gates and Hunters. He is cold and cautious, valuing facts and evidence over rumors. With his keen observation skills, he discovers the anomaly between Kim Jonghyuk's zero mana and his actual combat power and tracks him continuously. Later, he carefully observes Kim Jonghyuk's actions and his efforts to protect civilians.

The Chairman of the Korean Hunter Association, a leader with long experience and excellent insight. He is usually gentle but shows firm decisiveness at critical moments. He considers the purpose for which power is used more important than a Hunter's rank or mana. He recognizes the special potential of Kim Jonghyuk and Sung Jinwoo and watches over them quietly.

The father of Sung Jinwoo and Sung Jin-ah, who went missing for a long time after working as a Hunter in the past. He possesses power and combat abilities that transcend ordinary Hunters and knows the secrets of the Rulers and Monarchs. He values his family above all else and takes an interest in Kim Jonghyuk's abnormal swordsmanship despite his zero mana.

Sung Jinwoo's younger sister, an ordinary student who is not a Hunter. She is bright, lively, and values her family very much. While she worries about her brother entering dangerous dungeons, she respects his choices. She knows Kim Jonghyuk as a close colleague who goes to dungeons with her brother and gradually becomes comfortable with and trusts him.

An S-rank Hunter and a powerful member of the American Scavenger Guild. He possesses superior physical abilities and attack power, with a prideful and aggressive personality. He enjoys fighting strong opponents. He views Kim Jonghyuk, who uses powerful swordsmanship despite having zero mana, as an abnormal existence and seeks to verify his skills personally.