They manage to keep busy and appear to have much more going on in their lives than before.
You never know what your assassins are up to. NPC's actually change clothes and do things other than stand around and be annoying. I felt this could be expanded upon, so this mod picks up right after the main guild quests end, and gives purpose to running the sanctuary. In the stock game the player character takes over the job as listener, and from there simply acts as errand boy to Arquen the speaker, to fetch a mere 200 gold per week. This mod is being designed to bring more Dark Brotherhod content to the game, picking up where the stock game finishes. The Dark Brotherhood Expansion is a modification for Elder Scrolls IV: Oblivion.
