Hwang Dong-Su is a Korean S-Rank Hunter based in America and the younger brother of Hwang Dong-Suk.
Hwang is a selfish and sadistic sociopath with little respect for human life. He cared little as to what people thought of him, given his indifference to the fact that he is considered a traitor back home and arrogant to the point of stupidity.
At some point prior to the start of the storyline, Hwang was offered an upgrade by Norma Selner and defected to the America without a second thought, eventually joining the Scavenger Guild under Thomas Andre. This move caused the Koreans to consider him a traitor, and, as a result, his reputation plummeted back home in Korea.
Hwang's older brother was murdered in a C-Rank dungeon raid. Correctly deducing that either Jin-Woo or Jin-Ho, the two survivors of the dungeon, were responsible for his brother's death, Hwang then flew all the way to Korea to hunt them down and kill them.
Unfortunately for Hwang, by the time he caught up to Jin-Woo, the latter was stuck inside a Red Gate that had been bought out by the White Tiger Guild. Believing that Jin-Woo was as good as dead and that he had came to Korea for nothing, he gave up on trying to get information and returned to America the very next day.
Two days before the International Guild Conference, Hwang Dong-Su kidnaps Yoo Jin-Ho and tortures him in order to get revenge from Sung Jin-Woo. Jin-Woo finds Yoo Jin-Ho first using his shadows and then beats up the healer and Hwang before trying to kill him.
Hwang ends up getting killed brutally by Jin-Woo. Following his death at Jin-Woo's hands, he turns into a Shadow Soldier and is given the name Greed.