Dev Diary #248 takes a more in-depth look at the
Prospectorium, one of the new Specialist empires/vassals coming in
Overlords, along with a further look at Holdings:
https://forum.paradoxplaza.com/forum/developer-diary/stellaris-dev-diary-248-special-prospects.1517982/This bit gives a brief overview/description of each Specialist empire type, along with the key to how they play:
We are introducing three Specialist Empire types in Overlord.
The Bulwark: A bastion of defense that leaves basic resource acquisition to others.
The Prospectorium: Excels at resource acquisition but has weaker research.
The Scholarium: Specializes in research but relies on their allies for military support.
Similar to how Federations advance or degrade based on Cohesion, Specialist Empires improve based on loyalty, gaining additional perks and strengthening their bonuses and penalties as they level up through three tiers.
In other words, it appears Specialist vassals operate on a sort of rock-paper-scissors model, with each type improving their abilities as they "level up" via improving loyalty. I imagine it's supposed to work best for an overlord to maintain a "balance" of vassal types; I'm curious to see if that's how it'll actually work out in reality.
The dive into the Prospectorium is pretty damn cool. A lot of perks await this vassal type, even if they must suffer a research penalty as a result. I suspect the trade-off(s) could be worth it, however...
In the dev team's further reveal of Holdings, they mention that any of those that provide benefits for the overlord are like Criminal jobs, in they cannot be de-prioritized by the vassal. So you don't need to worry that constructing that slave facility on Anteres V will get shut down by the local government.
In addition, we get a look at some of the Holdings for Necroids, Machine Empires, and...others.
A couple of the "normal" ones:
Necroids:
Rogue Servitor:
Lithoid with the "Calamitous Birth" origin (I would *not* want this one on my planet!):
Speaking of Origins, they also revealed that the five included in the Overlord DLC are Imperial Fiefdom, Teachers of the Shroud, Slingshot to the Stars,
Subterranean, and Progenitor Hive. Sounds like each one will get a detailed preview from various content creators (one each week), with them also being summarized in that week's respective dev diary. I'm especially interested in the "Slingshot to the Stars origin, though I'm intrigued by Subterranean as well.