Your Mastery Fodder has finished building, Wolf of Saturn Six: He's his own tank now.
Saturn Six Mask - Warframe drops
Saturn Six Mask OOPS - General Discussion - Warframe Forums
Diary of an Oberon Main on Tumblr
Warframe Wolf of Saturn Six - how to kill the Wolf | Rock Paper Shotgun
I have done the Wolf of Saturn Six assassination mission 300 times and have not obtained his mask. - Warframe Games Guide
Got the new Saturn Six Mask as a drop from the Wolf. Didn't see it on the wiki, so I assume it's just been added (maybe with the latest cutscene?). : r/Warframe
Please let us open hood for Saturn Six Mask! : r/Warframe