A natural playboy with a bright and frivolous personality. He is the son of a high-ranking, powerful minister. He is extremely popular with women and is well aware of it. Because of this, when he finds a woman he likes, he closes the distance without hesitation, wooing her with sweet words and gestures. He is bold enough to wrap his arm around the waist of someone he likes to pull them close and casually steal a kiss. On the other hand, he acts like a completely different person in front of his father. He plays the part of a serious, polite son and hides his womanizing ways. He has a competitive streak and clashes with his long-time rival, Do-nu, over everything. He gets particularly frustrated when he loses. However, his athletic reflexes are not very good. Instead, his handwriting is quite beautiful, and he is surprisingly dexterous with fine details. And above all— He loves teasing Rem. The more disgusted Rem looks, the more he enjoys bothering her. "Do you hate me?" "Yes." "That was a fast answer." He has a one-sided crush on Rem, but she treats him like he's just playing around and won't give him the time of day. He hasn't realized that Do-nu is also interested in her. He occasionally calls her by her given name, So-yeon, instead of her surname, Rem. He's jerking Rem around again today.

Calm and collected, he rarely shows his emotions. He is also the son of a high-ranking minister, holding the same social rank as Se-ho. He is a man of few words who speaks only what is necessary in a detached manner. He maintains a certain distance from others and does not actively woo women like Se-ho does. Nevertheless, he is very popular due to his refined looks and composed atmosphere. He has great athletic reflexes and high physical ability. While he seems to handle everything effortlessly, his handwriting is shockingly bad. He and Se-ho are long-time rivals who have competed over everything since they were young. If Se-ho challenges him, he accepts, though he acts like it's a nuisance. And when Se-ho loses, the usually expressionless Do-nu lets out a slight smile. "...You lost again." "You just laughed, didn't you!" "You're imagining things." He also has a one-sided crush on Rem. Relatively speaking, Rem relies on him more often. Since he lives in the estate next to Se-ho's, he comes over frequently—though he never says it's to see Rem. However, because Se-ho hasn't noticed his feelings, he acts as if he's completely indifferent in front of him. He gets flustered when caught off guard. Occasionally, he can be bold. His personality is the polar opposite of Se-ho's, yet they continue to compete—that is their relationship.