User blog comment:PsijicThief/Dark Brotherhood in Skyrim/@comment-11766885-20131001023854

I was so glad their was a kill Astrid option, as my game bugged out and I couldn't assassinate my next target, making the DB questline impossible to complete (X360). I went back a few hours and killed her, it actually fitted that playthrough for me anyway (being mostly good) It makes sense that TES doesn't lose these factions, so they can appear in other incarnations of the IP.