I generated a vanilla 40d16 world medium sized. Usually the world gen stops at 200, but the megabeasts just wouldn't die. They survived until the year 420.
So let me look this up in legends, ah, here we are.
Anir Lumatem Tol Ecod, Male, pot smoking, Titan. D. 419, the megabeast that caused the worldgen to end on 420.
In year 2 he attacked the Elf's and became an enemy of The Tundra of Liberty.
In year 3 he attacked the Dwarfs and became an enemy of The Raw Pick.
In year 4 he attacked the Humans and became an enemy of The Padded Fellowship.
In year 14 he attacked the Goblins and became an enemy of The Lie of Bases.
In year 62 numerous humans began worshiping him, probably for his pot smoking ways.
In year 101 he became the enemy of another Elf civilization, The Humorous Clouds.
The rest of his life he went about threatening and beating people into his way of thinking. Losing his eye in the process, after-which he probably smoked pot out from his eye-socket because he's awesome like that.
He was the enemy of 34 Groups/Civilizations but don't worry, he's a peace loving, pot smoking titan. He only killed 99 people.
He was killed by a human fishery worker. A laid back fisher was probably too chill for Anir to fight back against. The fishery worker was actually a heretic who worshiped 5 other gods, but not Anir.