Baek Yoonho is a prominent supporting character who serves as the Guild Master of the White Tiger Guild, one of South Korea's most influential hunter organizations, and is himself a powerful S-rank hunter. His abilities are rooted in transformation magic, allowing him to take on the characteristics of a massive white beast. This transformation significantly enhances his physical strength, speed, and durability, granting him sharp claws and prominent fangs. While he prefers to use a partial transformation that keeps him in a more human-like state for better control, he is capable of a complete, full-body transformation when a situation demands his full power, such as during the high-stakes Jeju Island raid. A notable and unique skill he possesses is called the Eyes of the Beast. This ability allows him to enter an enlightened state where he can accurately measure the power level of other hunters or monsters with a single glance, a skill that also sharpens his reflexes. Despite his S-rank status, Baek Yoonho is considered to be on the lower end of the power scale compared to other S-rank hunters from around the world.

In terms of personality, Baek Yoonho is an ambitious and serious individual who carries himself with the authority expected of a guild master. He is deeply committed to the safety and well-being of his guild members, a trait that drove him to leave his previous guild and found the White Tiger Guild himself. This protective nature is a core part of his character; he has been shown to confront other powerful hunters who threaten his subordinates. Beyond his professional ambition, he is notably perceptive and curious. In fact, he is one of the first people to recognize that the protagonist, Sung Jinwoo, possesses an unlimited potential for growth, correctly deducing that Jinwoo's abilities were far beyond his official E-rank rating. While he can be intense and demanding, he is also capable of humility and camaraderie, forming genuine friendships and showing respect for the strength and leadership of others.

His background prior to becoming a hunter is that of a firefighter, a profession that instilled in him a strong sense of justice and a drive to protect innocent people. This past continues to influence his motivations as a guild master, guiding his decisions and leadership style. Baek Yoonho plays a significant role throughout the main story, most notably during the Jeju Island raid, where he serves as one of the frontline fighters against the ant army. His key relationships include a close friendship with Min Byung-Gyu, a fellow S-rank healer, with whom he shared a drink and discussed personal matters before the dangerous Jeju Island mission. He also maintains a professional and mutually respectful relationship with Choi Jong-In, the master of the Hunter's Guild, as well as a growing respect for Sung Jinwoo as he witnesses Jinwoo's incredible rise in power.

Throughout the story, Baek Yoonho undergoes a notable development. His initial confidence as one of Korea's top hunters is humbled after facing enemies of overwhelming power, such as the Ant King on Jeju Island, from which he barely escapes with his life. This experience forces him to re-evaluate his own strength and the nature of true power. In the epilogue, after the world is changed by the Cup of Reincarnation, Baek Yoonho is no longer a hunter. Instead, he returns to his original calling as a firefighter, working alongside Sung Il-Hwan and finding deep respect for him as a leader. In the sequel series, Solo Leveling: Ragnarok, he re-establishes the White Tiger Guild, now focused even more on saving lives in accordance with the philosophy he admires in Sung Il-Hwan. He also becomes a father to a daughter named Baek Miho, who inherits his transformation abilities and becomes the guild's vice-master.