You Hee - yeol has been the sole member of Toy since 1996 .
However , after releasing Toy 's debut album , Yoon Jeong - oh left the band to study overseas and You Hee - yeol joined the navy for his mandatory military service .
You Hee - yeol has been the sole You Hee - yeol of Toy since 1996 .
However , after releasing Toy 's debut album , Yoon Jeong - oh left the band to study overseas and You Hee - yeol joined the navy for his mandatory military service .