When the Blackbeards where introduced in chapter 234. They first show their appearances separately. Such as:
The sniper when he shoot the bird
The doctor/camel when he gave an apple to Luffy
In the same chapter, Rockstar was introduced as a new RedHair member. But what is the purpose of him being introduced. I am thinking now that Rockstar was actually a Blackbeard that was sent to spy to Shanks.