Board Thread:Warhammer 40k General Discussion/@comment-3416287-20141003063211/@comment-72.93.46.215-20141005000711

You need to decide where this planet is located. Segmentum Obscurus? Umlima? Solar, probably not. Tempestus? Pacificus?

For the other space marine chapter, I recommend the Red Talons. Since the Mechanicus is so involved here I would think they would call on the Iron Hands and their successors first; being close allies and all. Captain Gathedion of the 5th leading also the 6th, 7th , and 8th.

From your synopsis I imagine the Dark Eldar playing a significant part, since their entire wellbeing could be jeopardized if this goes bad for them. How about the Kabal of The Last Hatered and the Kabal of the Obsidian Rose, supported by the Wych Cult of the Blade Denied. A fluffy yet not played up group. Lead by Archon Bakzundis of the Obsidian Rose