The very first ''official'' Dark Brotherhood business that you are to handle is as intriguing as it is fun. After the Dragonborn does what he needs to do, losing his innocence, so to speak, he awakens in a shack where Astrid will guide him. Although showing some kind of gratitude for killing Grelod, the assassin does point out that, given the fact that the Aretino child performed the Black Sacrament, the player owes the Brotherhood a kill. After all, a contract was signed. Sort off.
The best part of it is she doesn't even tell the player who he has to kill, because in the shack with them lie 3 characters. Tied up and on his knees, one of the prisoners has a contract on his head and it's the Dragonborn's job to figure it out and kill him. Well, actually it doesn't matter, because even if the player kills 1, 2 or all 3, the job is done.
Now, considering the player already decided that he wants to join The Brotherhood, which we pretty much have already established that he does (right??!!), he has to join Astrid outside the Sanctuary, near Falkreath. Awesome, right? There is another way of completing this quest, I guess, though very, very depressing. The Dragonborn can kill Astrid as well and thus forfeit all future connections with The Brotherhood.
Who would want that, right?
