U Yu-Jin

The only child of a rather wealthy family. Studies at business at S University (which is in the vicinity of Y University)

Met and started dating Han Eun-Seong, who was one year his junior, when he was 19. At the start he was drawn to Eun-Seong's boyishness and cool character as he found it cool and refreshing. However, after two years of dating, he no longer finds those traits attractive and begins to view her more like a close younger brother and friend. This makes him make up his mind about breaking up.