I've probably had quite a few, since I usually play my fortresses for many years, giving my military time to grind up to legendary and able to wipe out entire civilizations with a stick and some string. But a couple stick in my mind:
Reg Liruklor:
http://www.bay12forums.com/smf/index.php?topic=65866.0Reg was just a normal dwarf in a normal squad of normal hammerdwarves. Wait, no, actually he was in a squad of hammerdwarves who had racked up a couple hundred kills (including beasts and mounts and so forth) and he had one total kill. One. It wasn't his fault, he happened to be off duty or downstairs or something whenever the invaders would show up. He had legendary skills from all the sparring, so he was capable. The roll of the dice sort of thing.
Then one day he was by the front gates when a squad of pike goblins showed up from the edge of the map closest to the gates. So they were nearly on top of the fort. Of course, being a dorf and having very simple brain functions (outside of the vast amount of brainpower taken up for "how to be drunk") he charged the whole squad all on his own before the rest of the military showed up. I figured that was it for Reg.
Instead, he went into a martial trance and became a vicious force of death. Eight total killing blows among all the other damage he caused that scattered the entire squad before the rest of the military showed up to clean up after him.
Reg Violenttool, the Basic Luck of Irons. Awesome title for a very dorfy dorf.
The other one was Atir Stigildegel, the Legless Hero of Diamondrelic:
http://www.bay12forums.com/smf/index.php?topic=83136.0Atir lost his legs early in the history of the fort, I forget how, but I kept him in the military since he had become a pretty good marksdwarf. And really, you don't need legs to stand there and shoot a crossbow. So here goes Atir, dragging himself around the fort with no legs, going between marksdwarf practice and weaving cloth. For a good eight years he does this, becoming a legendary weaver in the meantime.
Sadly Atir was ... he moved slowly. No legs and all. So he kinda, well, never showed up in time to kill stuff. So even though he was a legendary marksdwarf I think he had maybe two or three kills. So I always pictured this dwarf huffing and puffing as he dragged himself by his hands and beard to get to duty on time, arriving too late to take part in the action, then stoically dragging himself back to his loom to weave and slowly make his way downstairs to collect webs, only to bring them back up and continue weaving. And the thing is, he
always showed up, eventually. He was one of the most diligent and consistent dwarves in the fortress.
And then one day I get the notice that a Forgotten Beast shows up. I call my military to the panic zone where I set them up, between the caverns and the rest of the fort. Fortunately my military is well trained and should have no problem taking the beast out, despite the fact that it's made out of stone. Unfortunately, it is also moving
very fast and I'm not sure my military is going to get to the panic zone before the beast does.
Then I notice that the Forgotten Beast is fighting on the stairs with some unlucky dwarf about to get his head pounded in in short order. So I figure, well that'll slow it a little bit. Oh how wrong I was. It was Atir, coming up from gathering webs to go on duty.
Remember, Atir has been at this for a long time now. He's grappling with the beast, and since I cross-train all my marksdwarves with hammer skills, he's
beating the snot out of the thing with his crossbow. For seven pages of combat reports, Atir dodged, blocked and parried every single attack from the beast while breaking chips out of it and even ripping a mandible off. By now my military is in position but I'm just watching this epic battle between a Conglomerate Forgotten Beast and a legless dwarf hitting it with his crossbow and somehow dodging every clumsy swing it makes.
Then the beast got a lucky shot in and hit Atir in the head. At least it was fast.
Meanwhile my military has had plenty of time to get into position and made short work of the beast when it got to the panic zone. It put up a little bit of a fight, especially relative to the steam and water and snot beasts I'd mostly had so far who would die when you looked at them crosseyed.
An iron sarcophagus (because what military dwarf wants to be buried in some sissy metal), two golden armor stands and two golden weapon racks adorn his mausoleum. It was the first one I built in that fortress. Just for Atir. There was much drinking in honor of Atir that night.