Gandhi has been historically the most aggressive character in Civilization due to an original bug in the first game that caused him to go all-out once he reaches democracy. They just kept the thing going ever since.
To further explain this bug, because I was chatting with mothmonarch about Civilization and other strategy games last night and I never got around to explaining this fully, but I love this story:
Gandhi’s AI in the original game had its aggression set to the absolute minimum (0 on a scale of 0 to 10, I believe, I may have this wrong but the basic idea I’m about to explain is accurate, as far as I can tell). Adopting democracy lowers an AI civ’s aggression by 2 points, so when someone who is fully peaceful loses two points of aggression, they should still be nice and polite, right?
Except this is an old DOS game, and so computer math is in place. What actually happened was that Gandhi’s aggression level ticked backwards two steps, from 0 to 255. On a scale of 0 to 10, Gandhi is now 255 points of pure nuclear rage.
And that’s the story as I recall it, but again I may have gotten some details wrong, so feel free to correct me! After that, as the original poster said, the devs loved the bug so much that they just kept it in as a running joke!