I'm still pretty new to DF; I've had probably a couple dozen fortresses now, none of which was anything particularly special (discovered HFS in one recently, which was... enlightening). I've started digging around in Legends Mode in a new world I created and thought I'd share some of the more unusual or interesting things I've discovered in this world. Some of this may not be all that unusual to veteran players, but perhaps it will provide some amusement.
I'll mention beforehand that this was on a vanilla world running for 250 years and that I researched the information using Legends Viewer.
A human civ named The Kind Pink Realms has been ruled for a demon since almost day one (seriously, the demon didn't want to change the name?). Their flag... is blue.
The elf civ The Skins of Heaviness, have been under near constant attack during their entire existence. During this time they've had 46 queens. Average number of rulers in other civs during this time: 5. All but two of those 46 rulers were killed in combat, and 27 of those were during one war. That war was ended by a new elf queen who killed and devoured 81 of the attacking dwarves in a single month.
Twenty-six percent of all deaths in the world, ever, were 18,500 elves during a single conflict - during that conflict the aggressors lost only 3,700 dwarves.
Along the same theme is a situation in my current fortress where it appears that there is a deity being worshipped whose only followers are five elves and my mayor - and it's a deity of gambling and deformity. This cracked me up when I noticed this, though I bet I'm probably missing something about the way followers are counted in a deity's information.