Yoon Jaehyuk : 윤재혁 : or better know as Jaehyuk issa member of the group Treasure. Jaehyuk born on July 23, 2001 in Yongin, Gyeonggi Province, South Korea. His position on Treasure is vocalist and dancer. Jaehyuk is using a 𝗅𝗂𝗈𝗇 emoticon to symbolize himself. Jaehyuk issa Jokester, but Jaehyuk is also soft-hearted and affectionate person. Jaehyuk has a nickname YoonSweet because of his sweet personality he is nicknamed YoonSweet. When Jaehyuk is still a child, he was dream to become a businessman just like his father who is a Ceo

In November 2018, Jaehyuk participated as a contestant of YG Treasure Box, a survival show produced by YG Entertainment. He got into Group B with other trainees. All of the contestants were competing to get a place in the final lineup for YG Entertainment’s upcoming boy group. At first, Jaehyuk had difficulty adjusting with the other trainees. He also never received a compliment from the producer, Yang Hyun-suk. As time went by, Jaehyuk improved his skills which allowed him to receive praise from Yang Hyun-suk. Unfortunately, Jaehyuk was eleminated in the 9th episode, but he returned and successfully made it in the final lineup for Treasure.