Black Legion and the Children of Torment in particular. I know some feel Devram Korda is inferior for being thwarted by the Emperors Children post heresy, but the guy has lived through two Offico Assassinatorium Execution Squads, gotta respect that.
And I found one about ...ahem , we will agree on natural feel of it as we all have seen something similar before. Its funny and ridiculous at the same time. Just like the Imperium and it agents. I definitely want to see an inquisitor ( an actual character or npc, not our community member baring the same title as a name ) running around like this screaming such creative threats. Enjoy this before returning to the thread real subject.
In reality, it comes from a mixture of Black Legion being the poster legion, and not featuring much fluff outside of the Codex. The other Legions have books, and a narrative in that perspective forges a personal connection, so now that ABD is writing one about dear ol Abaddon, you'll be seeing an influx of Black Legion fans. Also, people tend to believe that the Black Crusades were all meant to seize Terra, so it appears that he failed twelve times in a row. And the arms of his model fall off. Plus just for the sake of ripping on things.
But even if all that were true, how can you deny that paint job?! That's the real reason the Black Legions so big.
Iron Warriors are more of what I would like to play from a role and lore standpoint. Tzeentch's witnesses are a bit too unholier-than-thou for me. The Black Legion, and each of their prior iterations, are far too focus on their own personal goals. I do love the Lords of Night though. I simply prefer the Iron Warriors and would play a Havok if I played chaos.
I really wanted to play as a Noise Marine in the Emperors Children, but I'll wait for their introduction and play as a my 2nd favorite legion, the Word Bearers.