Before anyone asks, I haven't started the new series currently airing yet. But I have seen the original run and the movie remakes as well as Resurrection.
Kallen Kōzuki (紅月カレン Kōzuki Karen) is one of the main characters featured in Code Geass: Lelouch of the Rebellion, as well as one of the two protagonists of Code Geass: Lancelot & Guren. She is officially known as Kallen Stadtfeld (カレン・シュタットフェルト Karen Shutattoferuto), and goes by this name at school, but prefers her mother's maiden Japanese name during her revolutionary (now military) activities.
C.C. (シーツー Shītsū), pronounced "C2", is one of the main characters of Code Geass: Lelouch of the Rebellion. She was the leader of the Geass Order before disappearing due to the murder of Marianne and the leader of the Order of the Black Knights until she returned Lelouch's memories. She was also the one who gave Geass to Leila Malcal and Lelouch.
All Roleplays are discussed in Messenger. This is due to how I'll be operating with Kallen. The gachas allow for variety for versions of the character. I'll have an album dedicated to the alternative versions for variety in RP. I do write both C.C. and Kallen, yes.
If I have added you then you can view the Variants for RP: