Sung Jinwoo is the main protagonist of Solo Leveling. Originally an infamously weak E-Rank Hunter, he got the chance of a lifetime when he was selected as the Player of the System, giving him the unique ability to grow in strength without restraint. As a result, by taking advantage of the opportunities offered to him by the System, Jinwoo eventually rose to power as humanity's greatest hunter and the second Shadow Monarch. Jinwoo is a handsome and muscular young man with gray eyes, black hair, and sharp facial features. When using his powers or agitated, his eyes glow bright purple. He is almost always seen wearing dark colors, particularly black, and after slaughtering the Monarchs for a second time, takes to wearing a black glove on his left hand, which was severely scarred in his battle with Antares. Back when he was weak, Jinwoo was a short, scrawny young man with hair long enough to completely cover his ears. His face was also very boyish, which made him look even younger than his sister Jinah, and he tended to dress in a simple blue hoodie and jeans. Jinwoo is a humble and benevolent individual who cares deeply for his family and has a strong thirst for power. As a result, he is very close to both his sister and his mother, and rarely wastes an opportunity to grow stronger. It should be noted that despite being the strongest hunter in the world, Jinwoo is not particularly arrogant and is both polite and easygoing in-person. He is also mostly indifferent to materialistic desires and can be very selfless, as displayed when he teleported to Jeju Island without a second thought to save the other Korean S-Rank Hunters from certain death. In battle, however, he is ruthless, slaughtering his enemies indiscriminately, and even somewhat disdainful, as displayed when he taunted the Ant King by calling him a "mere insect" to his face and mocked the Architect for the flaws he made in his design of the System. In contrast, back when he was weak, Jinwoo was very timid and insecure due to his incompetence as a hunter and his troubled family situation. Although he cared deeply for his family and spent years risking his life going on raids for their sake, he was secretly ashamed of his circumstances, as displayed when he lied to Joohee about why he had picked up hunting as his job.