Daetan is a Worgen. Except he’s nothing to do with wolves - he’s a Ducken.
All this means is that, like the Worgen, Daetan and some other druids all went crazy because they experimented with shapeshifting magic and went too deep without understanding the consequences.
At first you just start laying eggs. It only gets worse from there. If you peck people, they also become Ducken. Everyone starts pooping everywhere.
What’s interesting is that Ducken have been a thing for a very long time. Unlike dirty old wolves, pretty much anyone who sees a duck wants to become one. Epidemics plagued Azeroth from time immemorial. The world grew dark. Ducks consumed all, and blacked out the sun with their numbers.
That’s when some of the last, slightly-sane Azerothians made a plea to the Aspect of Time. Now, this was also a duck. Everything was ducks. The Aspect of Time sent a group of those few Ducken who still had any sanity left, back in time to stop the plague.
Back and back the heroes went, leaving a trail of their remaining sanity and duck poop through the timeways. Each time they tried to stop the plague, they failed. They went back further, further and further, but were foiled at every turn. It seemed Time itself desired all to be ducks.
But that actually wasn’t the problem at all. The problem was that druidic magic is fairly easy to learn, only really requiring meditation and immersion in Nature to forge a connection. Coupled with the fact that anyone who sees a duck wants to become one, there lied the ever-present danger.
The group of heroes now knew how to repair the timeways, once and for all. While there were roughly seventy-three versions of the party working at cross-purposes to them, they quacked loudly at the others and scared them off. They knew what to do.
They had to destroy not the Ducken, but the innocent ducks and ducklings. They did this before the humanoids came to Azeroth. They also left versions of themselves peppered throughout history, maintaining the lie that ducks never existed, and genociding any that appeared. (They also perpetuated a lie that druidic magic is difficult, and that not all races can learn it.)
Yes, my friends, the real reason Teldrassil had to burn was that a duck was there. These chronofleets, who used to be the heroes, but their bodies were destroyed by Time, only their insanity kept their consciousnesses around… THEY crazied everyone. They convinced everyone that Garrosh was a murderer despite the fact that there was a war on. They whispered to Vol’jin. They even possessed Sylvannas.
And there is even evidence of this, of all of this:
Chromie is still a duck. See?
(Also the Daetan stuff.)