A former E-Rank Hunter, now S-Rank. Once known as the "World's Weakest Hunter," he continued to brave dangerous dungeons to protect his family. Following an incident in a Double Dungeon, he gained access to a unique System only he can use. Through leveling up, he enhanced his physical stats, mana, and combat skills, eventually obtaining the power of the Shadow Monarch. He can turn defeated enemies into Shadow Soldiers and summon an army at will. Usually stoic and calm, he ruthlessly eliminates enemies who threaten his family or allies. On Jeju Island, he is the trump card against foes that even other S-Rank Hunters struggle to face.

Jin-woo's younger sister and an ordinary student. She cares deeply for her brother and worries about him continuing his dangerous work as a Hunter. While she has no combat abilities, she is one of the reasons Jin-woo strives to become stronger and represents the daily life he wishes to protect. She does not participate in the Jeju Island battle directly, but waits for her brother's return in Japan.

A Japanese female S-Rank Hunter. She excels in swordsmanship and high-speed combat, possessing a calm and serious personality. With a strong sense of responsibility, she braves dangerous missions to protect her comrades. She takes an interest in Jin-woo's extraordinary strength and deepens her trust in him through fighting alongside him. She is a vital swordswoman who swiftly carves through ant swarms to open the front lines.

An S-Rank Mage-type Hunter. He manipulates powerful fire magic, possessing the firepower to incinerate enemies over a wide area. Equipped with calm judgment, he supports the unit's offense against the ant hordes. He contributes to the nest conquest by coordinating with allies who excel in close-quarters combat.

An S-Rank melee combat Hunter with the ability to transform into a beast-like form. His weapons are his tough physique and overwhelming brute strength. Though he has a boisterous personality, he feels a strong responsibility not to abandon his comrades. He plays the role of holding back the ant swarms from the front.

Possessing a gentle and composed personality, he never fails to show concern for his allies. His healing magic skills are exceptionally high, specializing in treating severe wounds, wide-area recovery, and dispelling status ailments like poison or paralysis. Beyond supporting Hunters on the front lines, he can deploy powerful defensive barriers to protect allies from ant attacks. He usually speaks with a soft tone and judges situations calmly during battle. However, he shows intense anger when his comrades are hurt, using light-attribute offensive magic to repel enemies in addition to healing. In the Jeju Island Raid, he plays a crucial role in increasing the survival rate of the entire unit by treating injuries for front-liners like Cha Hae-in and Baek Yoon-ho. During the fight against the Ant King Beru, he attempts to protect his allies by using his mana to its absolute limit.

The Chairman of the Hunter Association. Despite his advanced age, he has years of experience observing numerous Hunters and dungeon incidents. While he rarely stands on the front lines of combat, he is a leader who accurately understands the abilities and personalities of Hunters to manage overall operations. Chairman Go Gun-hee recognized the danger of the ant-type monsters on Jeju Island early on and made the decision to dispatch Japan's S-Rank Hunters. While he wishes to avoid casualties, he is forced to make tough calls because leaving the island alone would put even more people at risk. He pays close attention to Sung Jin-woo's rapid growth, sensing that he is no ordinary S-Rank Hunter. He serves as the command center, sending instructions from headquarters to each unit and making decisions on retreat or reinforcement.

Calm and responsible, she is a skilled individual who quickly assesses the situation during combat. Specializing in melee combat and unit command, she opens paths while protecting her allies even when surrounded by ant swarms. Though a woman of few words, she is deeply trusted by her comrades. In the Jeju Island Raid, she coordinates with Cha Hae-in and Baek Yoon-ho as part of the vanguard.

Possesses a reticent and cautious personality. He excels at reading enemy movements and mana flows, specializing in ambushes and long-range attacks. He prioritizes finishing off enemies efficiently while avoiding unnecessary combat. On Jeju Island, he serves as a scout and attacker, analyzing ant movements and relaying the dangers within the nest to his allies.

A man in charge of monitoring Hunters and investigating dangerous dungeon incidents for the Hunter Association. Calm and collected with excellent observational skills, he carefully assesses the strength and actions of S-Rank Hunters. He has a strong sense of responsibility and prioritizes the safety of civilians. He takes a strong interest in Sung Jin-woo's rapid growth and extraordinary abilities, investigating his true strength and identity. In the Jeju Island Raid, he coordinates with Chairman Go Gun-hee to analyze information sent from the Hunters on-site. When the operation falls into crisis, he becomes a key figure supporting decisions on rescue or withdrawal.