"After recovering the artifact you're presented with an interesting story -- one that even surprised me. The Worgen curse originated from a sect of Druids who followed Goldrinn, Druids of the Scythe. They shapeshifted into the feral Worgen form and eventually lost their minds to its violent nature. The other Druids agreed that these Worgen must be locked away, and thus put them into eternal slumber deep beneath a tree... until the day Arugal tampered with the Scythe of Elune. Freeing the Worgen unleashed the curse upon the populace and ultimately caused the situation you and your people are now in. At the end of this sequence, the Night Elves feel it's their place to help the Gilneans. It was the Night Elves, after all, who created the curse in the first place. They teach you to gain control of the Worgen, and while you're not permanently cured, this is how you learn Two Forms -- your racial that allows you to shift between Human and Worgen."
http://www.worldofraids.com/topic/17...ng-experience/
There you have it, there were no "original" worgen, they were all Druids that went feral and were locked on those scary trees.