Kai appeared in a Korena production of a musical based on a book by Gaston Leroux released in what year?
Kai (musician, born 1981):  He is best known in musical theatre, and has starred in Korean productions of "A Tale of Two Cities", "The Three Musketeers" and "Phantom". Phantom (musical):  Based on Gaston Leroux's 1910 novel "The Phantom of the Opera", the musical was first presented in Houston, Texas in 1991.
1910