Found this on steam forum
https://steamcommunity.com/app/1575940/discussions/2/572665855469477356/
What kind of 4-winged 2-handed Watcher or how are/were those called ?
4th faction are gonna be space cannibals ? One could wonder, where does all that come from ? Babylonian Talmud ? 
Or its gonna be space talmudists (not very different to nazis, witchcraft practitioners both) trying to wipe out all life because they need to show whos boss. Advent is already a bit like that, rebellious from the normative of the TEC, even though the TEC is portrayed as hopeless oligarchical society in decline (inability to expand endlessly ?), where muh money takes priority, Ueber Alles. Its population should be declining due to very low living standard.
4th faction seems reminiscent of IRL US empire where everything is about power projection, subversion, self-image of saviors, while showing no mercy toward those who they coup or otherwise take over, or via economic, or military means, especially by proxies, who they constantly appear as if trying to restrain, while acting out aggression via said proxies, while pretending to negotiate between their targets and proxies on their strings they murder to tank their damage for the empire, while the empire squeezes all economical benefits, while exporting costs and damages (like they ordered EU/NATO subordinates to prepare themselves to be cannon foddered for the empire on its behalf)
The decadence and perversity, smoke and mirrors, peace on the lips while carrying a dagger, preparing to strike at both their vassals and their non-subordinates meaning their default enemies. Constant warmongering and blood lust, childish bravado to hide waning strength.
Maybe we will discover the 4th faction was prompting aggression, division between all the factions from the get go, they were just deemed harmless observers.
Like those pyramidal derelicts, starbases of the same form tier 3 space loot showin some cap /supercap derelicts like those Reaper derelicts.
4th faction could be the alter-ego of the US empire IRL, where TEC is the US with its addictive consumerism and accompanying cultural decline, Advent being the protestant fervor with satanic overtones, which is central to US imperialistic identity, while the new faction is who outside the US people know the US to be like, coups, warmongering, training terrorists, waging proxy and not so proxy wars of unprovoked aggression. Until it runs out of foreign cannon fodder and assets which they stole anyway. Biological, (supplying Iraq, including with West Germany, Zyklon B fame, chemical bio, also imported ww2 Japanese unit which did experiments against people, Vietnam Agents Orange, Blue etc.) chemical warfare. That is not to forget the treatment against the Indians. Biggest slaveowners preaching so-called equality Thats hilarious. And on top of that they cite this as being reason for their aggression. They need to equalize others poorness with their unearned, stolen stuff apparently by more stealing and mass murder, we want to steal, they call that we want equality 
But its also always about peace. Give me everything you have, surrender unconditionally and I will think what to do with you, I will call that peace. If you surrender, I will order my puppets to throw you to war as cannon fodder. If you refuse, I will use my previously captured proxies to wage siege warfare against you if you have any objections.
Space epshtainians It could be blood for the blood god type of faction, who knows. I guess they do, but it could be something of this sort.
Sins2 Forums
But its also always about peace. Give me everything you have, surrender unconditionally and I will think what to do with you, I will call that peace. If you surrender, I will order my puppets to throw you to war as cannon fodder. If you refuse, I will use my previously captured proxies to wage siege warfare against you if you have any objections.
Space epshtainians