So I finally beat the Fallen Spire campaign (which, without spoilers, was beautiful and made me laugh and nearly cry for joy), and installed the final expansion... But now I'm having trouble understanding the Vengeance Generators. They say they gather power as ships die on its planet, and I assume the ships spawn based on how many have died there... but is it possible/safe to build on the planet? It seems like ships are randomly appearing there, and I'm not sure how to have it safely under my control or under my border, or whether that's possible.
tl-dr;
Do vengeance generators spawn ships on their own despite nothing dieing on the planet since taking it over/freeing it? And is it possible to safely control or free said planet?
Vengence Generators gather points when ships die in the same system. When enough points are reached, it triggers a spawn in that system AND a smaller spawn in EVERY other system containing a Vengence Generator where at least one unit has been destroyed.
Aka, the only way a Vengence Generator system is 100% safe to build in is if
a) you have captured the system and cleared out all spawned Dark Spire
b) You arrange to prevent AI ships from entering that system again (most effectively by destroying all adjacent AI systems)
c) You repeat this process for every other system with a Vengence Generator.
You can gamble on distant AI systems with Vengence Generators never having anything die, if you want, but be careful in that case. NPC units, such as Dyson Gatlings, Marauders, Neinzul Enclaves, etc, can all trigger a Vengence Generator without your involvement.