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Perhaps the biggest and most immediately noticeable change will be a series of war and surrender Events that trigger the longer a war goes on, and vary depending on who started the war and who is winning or losing it, to add some extra flavour flavor and ensure the player has an option to end the war they might not want to be in.
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Furthermore, the AI is more loyal to civilizations that it has had good relations with for a long time, favouring favoring those it is has well established trade routes with, and will be somewhat less inclined to be bribed into a war with those favoured favored civilizations by other sneaky war-mongers. This means that they’ll not just take their current diplomatic status with their partner into account when they make that decision to go to war, they’ll look back at your past dealings too. Make friends and trade with them, and they’ll be more likely to stick by you when you’re in need of assistance once the Drengin, Korath Clan, Yor or some other dreadfully mannered neighbours neighbors come knocking!
To prevent sneak attacks, when a civilization declares war, all of their ships are removed from the enemy’s borders outside of their zone of control.
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These diplomatic changes to how wars are started and ended should open the grand strategy side of Galactic Civilizations IV: Supernova up even more, with civilizations being more or less inclined to engage in long wars to achieve their goals and loyalty to old friends factoring into their strategic planning. Gamers with less of a martial-inclination will be able to enjoy their empire building with less threat from long and gruelling grueling wars that they cannot get out of, and defensive and diplomatic civilizations will be able to achieve their victory goals without the inevitable need to become an unwilling galactic conqueror.
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