Si Hyun Han

Han Si Hyun is a Trace who works for the NIS. He first appears in Trace 1.5 as a man interested in co-existing with the Troubles. His proposal is constantly shot down by the higher ups as the NIS refuses to fund a research. One night, while intoxicated with his own ability, he sees a Trouble and subdues it. This Trouble was brought to his household, tied up, and Han SI-Hyun continues to do unauthorized research/experiment on it. This research includes the Trouble being tied up in his basement, feeding it human food, finding out it's mentality. This Trouble was named Sarang. Sarang was originally extremely hostile towards Han Si-Hyun, but as days went by, he later grew affectionate towards Han Si-Hyun, and vice versa. (Source: Korean Webtoons Wikia)