Developer Livestream- Share your Thoughts

[Rollotomozi]

@WhiteRabbit

But am I correct to assume then that purges no longer happen at all unless you opt to initiate a purge?

yes
from patch notes:

@Spynosaur_Nicole

Purge Rework!

• Purges are now triggered manually by the player (through the Proclaim Wealth button in the new Coffer interface!)
• New Coffer Interface can also be used to sell treasures in your coffer for Gold Coins!
• Initiating a Purge will cause a Stygian Forward Operating Base to spawn nearby and begin sending waves of enemies to assault your base and steal your treasure!
• To trigger a Purge successfully there must be a valid path from outside of your base all the way through to the Coffer. Should this path be destroyed or blocked the Purge will retreat.
• Thralls can now be assigned to guard any doors in-game to help you defend from the new Purge, simply assign a thrall while hovering over one of the “ghosts” that will appear showing its assignment slot and confirming.
• Purge difficulty is scaled to the amount of treasure inside of your coffer!
• After a significant portion of your treasures are successfully stolen, the attacking army will retreat victoriously. (You Lose!)
  • Including enemies which will attack using the all new Battering Ram weapon to punch through your base even faster!
• Repel enough waves to trigger the Stygian Boss of the camp to reveal himself and join the fight!
• Killing the Boss will end the Purge, dropping keys to loot the FOB’s reward chests and release any captives that have been taken by the Stygian army! (You Win!)
• Captured prisoners that are released inside the Forward Operating Base can serve as your Thralls! As well as a chance for special prisoner (Mercenary Captain) who will act as a temporary store in gratitude to sell you special items to help you in future Purges!