Five personalities

Each country is assigned a persona whose weights scale its behavior. The five are Expansionist (aggression 2.2 — invades eagerly), Opportunist (aggression 1.7, betray 1.0 — preys on the weak), Hegemonic (aggression 1.5, sphere 1.8 — builds spheres and alliances), Mercantile (aggression 0.4, trade 1.9 — avoids war, trades hard), and Defensive (aggression 0.55, ally 1.6, betray 0 — leans on pacts and deterrence).

These multipliers feed directly into decision rolls. The aggression weight scales the chance an AI declares an opportunistic or grudge-driven war; the ally weight scales how often it proposes alliances (checked against a relations floor); the trade weight drives how aggressively it upgrades economic ties; and the sphere weight governs how much it pulls neighbors into its influence.

The betray weight is the sharpest personality signature. A Defensive persona has betray 0, so it will literally never launch an opportunistic backstab; a Mercantile persona (0.1) almost never does; while an Opportunist (1.0) actively hunts weakened neighbors. Notably, any highly aggressive persona (aggression > 1.4) also picks up a floor of 0.7 on its effective betray weight — so Expansionists join in on opportunistic strikes even though their base betray is only 0.4.