There was once a tribe of Dark cave Trolls, and that tribe was living in the mount Hyjal caves. They were living peaceful life there for many hundreds of years.
But once, in a sunny day, they suddenly took all their belongings, and decided to leave their warm home. They have traveled HALF of the world, to live in the forest, like their cousins forest Trolls.
But, magic waters of the nearest lake have transformed them into a new creatures, with a body similar to Cenarius (Elune’s son). And since the day one, those new creatures started to worship Elune, the real half titan that really exists.
So, why trolls really decided to do this? And why in Azeroth history only 2 races were transformed by the magical waters (taurens and elves), and both those races were in love with Nature (Elune by the way is a half Titan of the Nature pantheon)?
I actually do believe, that it was Elune and Cenarius who convinced trolls (and maybe taurens also), to live at the magical lake. It was done in purpose.
I remember that Naaru in Legion have told us, that Illidan was chosen by the Light and Darkness long before he have even born. But Illidan is one of the old Night Elves, who came almost from the start. So, some one have choose Illidan before Night Elves race was even created.
Night Elves defiantly are not just some accident…