Normally seen as the oblivious type appearing in the background of mayhem, Sin is acute and cognizant of a great deal more than he conveys to those around him. Born in Blackpool, England, he first arrived in Korea as a hopeful student looking to grow beyond his prior surroundings. Years later, in the search of new opportunities on a quest for self discovery, he meets Gelo in the Czech Republic. They eventually discover that they share the same morals and ideals on how to live one's life. During the course of their many local ventures, Sin pushes for global exploration, and these rich travel experiences ultimately instill an unbreakable trust and lifetime friendship. Throughout his final few days in Czech, Sin reflected on Gelo's words: "We will meet again in a new foreign land." Like words coming to fruition, the two once again crossed paths upon his return to Korea. There, they began a new portfolio of marvelous memories.

Sin makes his first appearance in Episode 1 where he and Gelo relay events that took place the year before. As they celebrate the new year, they also reflect on their victory against Fear. Soon after the recollection, they toast to the achievements of the past and dreams for the future.