Jin is Hana's employer. When Hana was an orphan, he sold her to the Triads when her parents were killed. Hana does odd jobs for Jin in order to get the money to leave the Triad and put her past behind her.
Fear Effect 1
When Hana meets Jin, Lam straps a bomb vest to Jin's chest and threatens to blow him up. As your first puzzle you need to defuse the bomb and get the information out of Jin.
Near the end of the game, he is revealed to be Yin Lau Wong, the king of Hell.
Fear Effect 2: Retro Helix 
Jin will give Hana the mission briefing at the start of each cutscene. The first you need to break into Wing Chune with Rain and the second you need to meet up with Glas and Deke in Xi'an.