Sung Jinwoo (성진우, Seong Jin-Wu) is the main protagonist of Solo Leveling. He is the strongest hunter in the world and the second Shadow Monarch, having inherited the position from his predecessor Ashborn. Originally an infamously weak E-Rank Hunter, Jinwoo 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.
Jinwoo is a humble and benevolent individual who cares deeply for his family and has an ardent desire to become stronger. As a result, he shares a close relationship with his sister and his mother, and rarely wastes an opportunity to refine his skills and gain more power. His deep bond with his family also makes him absolutely merciless towards anyone who dares to hurt them, as displayed when he massacred Groctar and his minions for attempting to kill Jinah, and murdered Hwang Dongsoo for torturing Jinho.
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, as he tends to slaughter his enemies indiscriminately, and even somewhat disdainful, as displayed when he taunted the Ant King by calling him a "mere insect" and mocked Kandiaru 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 financial 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 chosen hunting as his career path. However, his traumatizing experience in the Double Dungeon would give him everything he needed to become stronger, and being betrayed and left to die by his fellow hunters while trapped inside the dungeon would teach him the harsh lesson that his kindness could be exploited by others for their own benefit. As a result, from that point on, Jinwoo vowed to never again recklessly endanger his own life under the guise of the greater good and adopted a more self-preserving stance as a hunter, primarily focusing on amassing strength and eventually growing into the fearsome warrior that he is today.
