I will explain what I liked and disliked about each mod and why all of these leave me unsatisfied in the end. So unless there is a major mod which is not being shown to me while searching for 'Dark Brotherhood' I tried the first two and 'save the dark brotherhood' a bit further down. And no, the issues I faced have nothing to do with my game, because I tested them on a freshly installed skyrim on my Laptop. And I have to say I am deeply disappointed as most of them are outdated, CTD-prone and bugridden. So I spent the last couple of hours trying and testing the mods floating around the nexus which tackle the Dark Brotherhood.