1) Crota is the hive god like figure who killed countless of guardians. 2) That isn't Crota, that is a new npc coming to the game. 3) Yes and no. Yes it will give more details on the story perhaps, but also no because they are slowly releasing story missions as more dlcs come out later. I'm happy, as I've been waiting for the exspansions. I been having fun with the game and so have my friends. New exotics that I can't wait to obtain.