Playable vassals

[Leoreth]

Being able to play as a vassal is an often requested feature in my mod. I know it is easy to give humans the option to accept a vassal trade and become an AI's vassal, but I am not sure how much the rest of the game is prepared for that to happen and if there would be unintended consequences.

Does anyone have an idea what else I have to think of when deciding to enable this? Cases where the AI should factor in if the human player is a vassal? Is there maybe a modcomp to this effect that I could look into?

 

[f1rpo]

The BBAI_HUMAN_AS_VASSAL_OPTION has no effect beyond allowing such vassal agreements. While K-Mod enables the BBAI option by default, the K-Mod AI never agrees to accept a human vassal. So I've never had a chance to test the option in K-Mod. I did take control of an AI vassal once or twice and played for a few turns without encountering any obvious problems. My AI master offered me some gifts. I was able to break free by canceling the (non-capitulation) vassal agreement. I also recall seeing an AI resource demand with this text:

Spoiler :

<TEXT><Tag>TXT_KEY_VASSAL_GRANT_TRIBUTE</Tag>
<English>The %s1_civ (%s2_player) demands a tribute of %s3_resource. Will you comply?</English>
<!-- ... --></TEXT>
<TEXT><Tag>TXT_KEY_VASSAL_GRANT_TRIBUTE_YES</Tag>
<English>Yes, anything to keep them happy</English>
<!-- ... --></TEXT>
<TEXT><Tag>TXT_KEY_VASSAL_GRANT_TRIBUTE_NO</Tag>
<English>Never! (Declare WAR!)</English>
<!-- ... --></TEXT>

My main concern would be that the vassal agreement is too advantageous for the human side. The AI isn't going to get much value out of a human vassal. CvTeamAI::AI_surrenderTrade should arguably only accept if the human player is on the ropes, i.e. as a catch-up mechanism. Some smaller issues that come to mind:
* If a human player is unpopular, attitude averaging (CvTeamAI::AI_getAttitude; disabled in K-Mod) will also hurt the relations values of the master.
* By asking for a gift from a rival (or granting one), a human vassal can prevent its master from starting a war with that rival.
* Not sure if a human vassal is or should be forced to vote for its master in elections (when the vassal itself isn't a candidate).
* The master might let its guard down against human espionage.

 

[Leoreth]

Interesting, thanks for the info. That sounds mostly encouraging to me. I am mostly interested in this from a historical perspective, i.e. civilisations like Canada starting out as vassals of Britain. So maybe disabling becoming a vassal would be a choice, and it's mostly a question of how to make vassal status unappealing enough that attempting to break from it is encouraged.

 

[f1rpo]

Agreed; I don't see any major issues with letting humans start as vassals. Under mercantilist trade policy, colonies were prohibited from trading with other empires – but I expect that the DoC community could come up with a long list of historically informed drawbacks for vassals if you don't already have something in mind.

 

[Leoreth]

Yeah I am sure of that too I was mostly hesitant to tackle this subject from a gameplay/implementation perspective but it sounds like I can put it to discussion.