SJB-Shirt (X or Nicolas) is a male character exclusively in CrossFire China.
The GR side wears a dark blue suit with black leather shoes; however, the BL side has a vest with a red shirt and is wearing sun-glasses.
The character model appears to be based on a player who won a contest in CF China. One of the rewards of winning this contest was getting a character in-game which looks like you. The character's archetype is a Chinese Hong Kong actor, Nicholas Tse.
In 2013, just like Gloria Tang, Nicholas Tse became the first endorser of CF China. He created a song for CF China in same year; however, SJB-Shirt doesn't have exclusive voice pack like GEM.