Vassals are those factions that have surrendered to another in the course of the campaign.
Surrender[ | ]
A faction may surrender depending on circumstances:
- Social engineering choices: A faction is more likely to surrender to factions with social engineering choices favored by them (i.e. Yang and the Human Hive won't likely surrender to a democratic faction, but Lal and the Peacekeeping Forces will).
- Reputation: Positive reputation increases the likelihood of surrender; despicable leaders are perceived as prone to breaking agreements and finishing the job.
- Atrocities: Self-explanatory, atrocities reduce the likelihood of offering surrender.
- Diplomatic situation: A faction engaged in multiple vendettas is more likely to surrender to another.
- Power: A faction with a clear military advantage, particularly one that has quickly dominated the other by taking cities and destroying multiple units, is more likely to be offered surrender.
Effects[ | ]
Vassals are effectively forced Pact members. The suzerain faction enjoys the following benefits:
- Vassals are forced to vote in favor of their Suzerain in Planetary Governor elections and Diplomatic victory.
- Vassals are much easier to convince to back the suzerain's proposal (eg. launching solar shade), and will make reasonable demands in return for their vote.
- Vassals will generate trade automatically.
- Vassals will readily agree to military proposals, whereas Pact members might quibble.
- Vassals will trade any new tech they discover without problems.
Management[ | ]
There are two schools of thought when it comes to vassals: One is to keep them small and weak, so that you can benefit from their votes, but little else. This prevents them from being a nuisance, but will limit the military and economic benefits.
Another is to nurture it by providing the occasional technological advance, gifting bases, and generally treating them with kindness. It reduces the likelihood of a faction rebelling (making unreasonable demands might cause them to decide they have nothing to lose and everything to gain) and greatly increases the amount of commerce received and can supercharge your research efforts.