Protect the vassal - conditionally join the expansion

Protect the vassal - conditionally join the expansion

This is a vanilla mod and is currently in full conversion testing.

Compatible with version 1.19 (last updated on June 16, 2026) Lord Level Update (v0.2, June 20): I redid the mod so that the entire feudal chain can now be summoned to join the battle, not just the lords described below (I will update the mod description with details later; a summary of the redo below). In short: each feudal state will only join if it (conditionally) violates the modified balance defined below (each at their own discretion) or if the feudal state deems that the armies of the attacking vassal (as well as the summoned feudal state's armies) are sufficient to fight (if they are twice the size of the enemy and his allies). If the lord is a player, they will receive a personalized call to war (conditions); if they have a lord above them, that lord will factor into the force calculation whether you should join the war, and may join before you do. If the player is a vassal, the mechanism is not much different from the AI ​​vassal in this module. The only difference is that the player can summon other lords during the war (the requirements are the same, this is not a bypass), and is not subject to the restriction of automatic summoning at the beginning of the war. Future updates will include necessary fixes and graphical interface enhancements where applicable. Have fun! Please read (still in beta):

(1) The goals of the module are:

Expanded the "Conditional Joining" law to actually allow an overlord to join its vassal in a defensive war while keeping the vassal as the war leader ("Be Quick").

Allows both players and AI to protect their vassals without waiting;

Allows both players and AI to summon their overlords to join the war.

Allows the player and AI to work together to protect and be protected from adventurers of a hostile faith (if hostile to both the player and the AI).

(2) Conditionality:

If the overlord is AI, it will automatically join as long as the balance of the modifier is positive;

If the suzerain is a player, you still need to use the "Protect Vassal" interaction;

(3) Balance of correction values:

The original modifiers in tributary defense are retained;

New: (+) Great incentive for AI to defend vassals, almost guaranteeing they will join forces.

New: (+) If the AI ​​has the brave, honest, just or angry traits (if the overlord is at peace), a small amount of inducement can be given to protect the vassal.

New: (-) If the AI ​​has the cowardly or lazy trait, there will be a slight disincentive to protect vassals (the effect is doubled if the overlord is at war).

(4) Tributaries:

(I'm still not sure if this is possible, it looks like it's hardcoded, but the interface says it is).

The original modifiers in tributary defense are retained;

New: Custom modifiers mentioned in the above thread, except for vassals.

New: (+) AI defends the standard incentives of its vassals, reducing the probability of attacking them.

(7) Other information:

It is still in the testing stage and runs well, but bugs are to be expected, especially in the full conversion module;

Compatibility (modify interaction): join_vassal_war_interaction;

Other mods: The Lord of the Rings: Grace of the Firstborn.

Charlemagne and Hildegard by Antoine-Jean Gros