Chae Song-ah - Song-hee's sister, a late college student who entesd the same university's music college as a freshman after taking four college entrance exams while studying business administration at Seoryeong University
Lee Jeong-kyeong - The only granddaughter of honorary chairman Na Moon-sook of Kyeonghu Group, which ranks 15th in the business world, the only daughter of current group chairman Sung-geun and a violinist
Kang Min-seong - Song-ah's best friend, a friend from the college amateur orchestra club, when Song-ah was the general secretary, Min Seong-eun was the chairman, Dong-yoon is vice chairman, currently a Ph.D. in chemistry at Seoryeong University.
강민성 - 송아의 베프. 대학 아마추어 오케스트라 동아리 친구. 지금은 서령대에서 화학과 박사 과정 중.
Na Moon-sook - Started management classes as a secretary to her father, the founder of Kyeonghu Group and took over the company with her outstanding abilities, honorary chairwoman of Kyeonghu group, the mother-in-law to Sung-geum, dead Kyeong-seon’s mother