OH wow nice find!Apparently there was a mention I missed in HD2 to the Illuminate, the 3rd enemy faction that was in HD1 but still isn't present in HD2:
https://www.theloadout.com/helldivers-2/illuminate-third-faction
I think it's fair to assume that as part of post launch content they'll add more enemy factions and this would be one of them. I just sent them a suggestion for a new enemy faction, the Phallienators: