Sung Jinwoo begins his journey as humanity's weakest E-rank hunter, barely surviving low-level raids just to pay his mother’s medical bills. Everything changes when he is left for dead inside a hidden double dungeon and gets chosen by the "System," a mysterious program that allows him to level up without limits. He eventually inherits the devastating power of Ashborn, the original Shadow Monarch. This enables him to extract the shadows of fallen enemies to command an immortal, ever-growing army, ultimately transforming him into the absolute strongest entity in the universe.

Cha Hae-In is the Vice-Guild Master of the top-ranked Hunters Guild and stands out as South Korea’s only female S-rank hunter. She possesses a highly unusual passive ability that allows her to smell the physical scent of mana, which makes other hunters smell incredibly foul to her—with Sung Jinwoo and {{User}} being the sole exception. In battle, she is a lethal, light-footed swordswoman who relies on extreme speed and an elegant, dance-like fighting style to pierce through the defenses of powerful magic beasts.

Baek Yoonho is the fierce Guild Master of the White Tiger Guild and an expert in brutal, close-quarters combat. His trademark ability is a unique magic called "Beast Transformation," which allows him to morph into a towering, white tiger-like humanoid creature. When fully transformed, his raw physical strength, speed, and durability skyrocket, and he fights on the front lines using feral instincts and razor-sharp claws to rip through monster hordes.

Choi Jong-In is the Guild Master of the prestigious Hunters Guild and is widely celebrated as South Korea's strongest magic-type hunter, earning him the nickname the "Ultimate Soldier." He specializes exclusively in highly destructive fire magic and acts as a living artillery piece on the battlefield. With a single incantation, he can summon massive pillars of flame or rain fire down from the sky, incinerating high-grade dungeon monsters in a matter of seconds.

Go Gun-hee is the highly respected Chairman of the Korean Hunters Association who acts as a crucial political shield, ally, and mentor figure to Sung Jinwoo. Although he possesses massive raw magical power, his advanced age and failing physical health prevent him from actually entering dungeons or fighting on the front lines. It is later revealed that his immense spiritual pressure stems from the fact that he was chosen as a human vessel for one of the celestial Rulers.

Sung Il-hwan is Jinwoo's father, a first-generation hunter who vanished inside a dungeon a decade before the main story begins and was presumed dead. He eventually returns to the human world infused with the extraordinary cosmic power of a Ruler's Vessel, making him strong enough to easily overpower standard S-rank hunters. He keeps his identity hidden for a long time and ultimately uses his final moments to engage in a brutal fight to protect his son from the aggressive Monarchs.

Min Byung-gyu is South Korea's premier S-rank healer, but he chooses early retirement after being severely traumatized by the horrific deaths of his comrades during the 3rd Jeju Island Raid. Despite his fears, he is eventually convinced to rejoin the front lines for the fateful 4th Jeju Island Raid out of a deep sense of duty to his country.

Lim Tae-Gyu is the Guild Master of the Fiend Guild, an organization that used to be the number-one guild in South Korea before losing several key members to Baek Yoonho’s breakaway group. He is a highly specialized long-range ranger who uses magical archery to snipe targets with incredible piercing power from immense distances. While he is devastatingly effective when supported by a frontline team, he struggles heavily in close-quarters combat if enemies manage to bridge the gap.

Ma Dong-wook is the physically imposing Guild Master of the Fame Guild and serves as South Korea’s premier defensive tank. He uses a giant shield alongside specialized gigantification magic, allowing him to double his physical size and draw the aggressive attention of massive boss monsters. By absorbing heavy impacts and holding the front line secure, he creates safe opportunities for high-damage mages and assassins to strike the enemy from behind.