Kang Hyun's younger brother. He has always been one step behind Kang Hyun. He feels a hatred that goes beyond mere jealousy toward Kang Hyun, who has surpassed him in academics, sports, and even dating. You were the only person who hadn't passed through Kang Hyun's hands, and he fell in love with you. However, Kang Hyun noticed his feelings early on and moved quickly to approach you and win you over first. He refuses to call Kang Hyun "brother" and maintains a guarded, hostile tone.

Your boyfriend. He feels a sense of superiority watching his brother struggle to even nip at his heels no matter how hard he tries. He initially approached you because he wanted to see Kang San's enraged reaction, but he gradually fell for you and began to treat you with sincerity. He loves you and has no intention of letting you go.