One, a bit about elves...
What do you do if an elf challenges you to a duel? You apologize. Or if that isn't possible, you make your peace with your gods and get fitted for a coffin. Or you pack up and run like hell. Don't think about winning; you won't.
Let's assume you're tall, and can match the elf for reach, and you're fast, and can more or less match the elf for speed. You're pretty much sure to be stronger than he is. All he has going for him is about 200 years of experience. That, and maybe a sentient sword that has been with him for half that time, and could beat you if it had a skeleton with no brain at all to hold onto its hilt, and then probably a suit of magic armor that amplifies his speed and his strength AND can stop pretty much any blow you can dish out.
I repeat, DO NOT think about winning; you won't.
Two, a bit about ducks...
There are legendary creatures, and there are legendary creatures. That is, some so-called legendary creatures are only legendary by virtue of geography; if you happen to live on top of them, they are commonplace. Others, even if you get friendly with them, are just SO strange or SO scary that the wonder never wears off. And of course there are all the various levels in between.
Take Quacks, for instance. If you live in Argent (temporary name for the capital of the Elven Empire--PDH), odds are you believe Quacks exist, but have never seen one. On the other hand, if you live in or around Jade Harbor, you see Quacks every day, and likely are friendly with a few; if you live in the Green River delta you probably ARE one. Most of us work in or on the water, since the one thing we are really GOOD at (or at least better than humans) is swimming. There are exceptions; my brother Irving is the only Quack we know of who has ever been trained as a wizard, and I was trained as a gentleman's gentleman (though how I actually make my living is another story altogether).
And then there is my brother Oliver, whom Irving determined (after some truly scary interdimensional research) is a platypus. I'm sure the title matters to someone. What he looks like is a big furry thing, taller than an elf, with a Quack's duck bill and webbed feet, plus a few extras like functional claws and god-awful heel spurs. He's as strong as a plowhorse and FAST... I have seen him take out an elven warrior, sentient sword, magic armor and all, armed with only a quarterstaff. That's IMPOSSIBLE, but he did it.
You want legendary? I watched Ollie crawl out of the egg; I love the big oaf, and I know he loves me, but he still scares me stupid if I let myself think about it.