The reason it is called thief is for the plot being centered around the stolen book and amulet. A thief to steal the book and amulet is needed, or rather, you may choose to be anyone you wish to play! All that is needed are characters to bring the plot to life, so if you choose to play anything, its welcome^^ 
Also, kik is a messaging app used oftentimes for group conversations.

Plot suggestions are also welcome.