Jae Gi

Jae Gi works for Doo Ho, the fisherman. He delivers methamphetamine for him.

Jae Gi first sees Jong Soo at Kim's place. He sees potential in Jong Soo. Both being poor men wishing to make more money, they decide to start a drug dealing business of their own. He is handling the delivery while Jong Soo makes the drugs. Using Doo Ho's ledger, he seeks out potential buyers. He finds an interested client, who they convince him to deal with them. The business takes off soon after.

Doo Ho eventually finds out about their business and drags Jae Gi and Jong Soo back to his place. After punishing them, for dealing behind his back and competing with his business, Jong Soo and Jae Gi agree to hand their batch of drugs over to him. Jae Gi wishes to part ways with Jong Soo when he goes to deliver the drugs.

Jae Gi delivers the drugs to Doo Ho which were unknowingly switched out with another drug concoction by Jong Soo. Jae Gi watches as Doo Ho collapses after inhaling the product.

(Source: MyDramaList)