There are two hidden bastions of life in its wildest, farthest variety on Azeroth. One lies far to the north on the continent known as Northrend. The other is far to the south amid the deserts of southern Kalimdor. Each lies surrounded by Titan complexes and the ruined remains of the same (Azjol-Nerub and Ulduar in Northrend, Ahn'Quiraj and Uldum in Kalimdor), and each is protected by powerful constructs keeping them inviolate. Indeed, only in these two places do the creations of the Titans freely act to preserve the equilibrium of the environment.
In Un'Goro and Sholazar, life on Azeroth was developed. These were the experimental controls, the crucibles, the drawing boards, and the scrap heaps for all life. If the Emerald Dream serves as a kind of blueprint for the way Azeroth was intended to unfold without the interference of the Burning Legion or the Old Gods, then Un'Goro and Sholazar are the last places left where that blueprint is being followed. Linked not only by a common purpose but also by a massive Waygate, these regions have come under heavy attack from the servants of the Old Gods as well as the mindless hordes of the Scourge, testing their defense to the utmost.
What is interesting about this is the fact that it proves that the Old Gods did not create the concept of fleshly beings, and thus, their Curse of Flesh that is intended to render the Titan's creations vulnerable to assimilation may not have been their own creation. When looking at the vast and astonishing variety of flora and fauna in Un'Goro and Sholazar, one immediately notices that all these plants and animals are fleshly beings. The only stony constructs in these areas are clearly intended to patrol and maintain them, and remarkably few of the earthen, vrykul, or mechagnomes are present in either area. In short, when Khaz'goroth designed his petri dishes, he stocked them with living things.
The intent for the seed races may have always been to become flesh themselves or to serve as artificial templates for such beings that would, in time, have been created and given Azeroth to inhabit. While we don't know their origins, we do know that trolls, tauren, and elves have no seed race analogues as yet discovered. Despite this, we also know that the Halls of Lightning contain clear representations of all of these races alongside the seed races. Are the Old Gods so corrupt and lacking in creativity, in the ability to create at all, that they couldn't even create their own curse? Did they corrupt even that from a Titan-created process?
It seems difficult to argue that the Titans didn't intend for their creation to be inhabited by beings of flesh, considering that Khaz'goroth himself (itself?) created Un'Goro fully intending it to be stocked with all manner of flesh, from screeching pterrordaxes to towering devilsaurs.
Interestingly, in addition to the crystalline defense systems (and if those crystals make us think of a possible connection to the Naaru and Outland, well, there are devilsaurs in Netherstorm), another defense seems to be shared between the regions. Both have powerful Titan Watchers residing or assigned to them (Nablya in Un'Goro and the Avatar of Freya in Sholazar) and beyond this, a singularly powerful defensive unit shared between the two sites: The Etymidian.
The Avatar of Freya echoes Nablya's statements as to the purpose of both Sholazar Basin and Un'Goro crater -- but even more illustrative of their true nature, the two regions share this one defensive system. When those who choose to ally themselves with the Avatar step through the Waygate in Sholazar, they end up in one of the terraces in Un'Goro similar to the one Nablya inhabits. And in that terrace, after defeating Scourge agents who seek the power of the Titans for their own twisted ends, Freya's allies find the Omega Rune, and through its power, they awaken the Etymidian.
With the Avatar using the Omega Rune, the Etymidian can be summoned to Sholazar from Un'Goro. This is potentially a safety feature to keep the construct, described as "one of the most destructive forces ever created by the Titans," from wandering around under its own direction; considering that the Titans made Algalon, who has destroyed entire worlds, either Freya's avatar is exaggerating, or the Etymidian's power was barely tapped by those that used it. When it is summoned, it decimates hundreds of Scourge, destroys their powerful leaders, and effectively ends the Scourge invasion of the basin by itself. Considering that the silithid and Qiraji feared to cross Un'Goro Crater when they fought their great war against the night elves and Bronze, Red, Blue and Green Dragonflights, one wonders if the Etymidian was awakened then as well.
The Avatar of Freya says the Waygate has not been opened for seven centuries, which seems oddly recent. Does this correspond with the events of the Prophecy of C'thun? Perhaps the reason the Etymidian is sleeping in Un'Goro is because it stepped through the Waygate last to stop the Qiraji from taking the crater: "They could not take the God Lands."
So it has been since their creation, and so it is today: Unlike other regions of the world, where the forces of life are allowed to play out their conflicts, the twins Un'Goro and Sholazar exist to provide places for tinkering on a scale effectively impossible for most beings to even grasp. Even more interesting than the intertwined nature of these two zones and their defenses is their astonishing variety of life.
The implications of these two experimentation sites go far beyond diversity and iteration. They imply that the process that took place in Un'Goro and Sholazar is so crucial to the development of Azeroth that astonishing levels of force will be deployed in its defense, and furthermore, that not even servants as highly placed as Loken or the Tribunal of Ages are privy to its full extent. Fleshly life existed before any curses, and beings of inexhaustible destructive power were created solely to ensure its continuance.
While you don't need to have played the previous Warcraft games to enjoy World of Warcraft, a little history goes a long way toward making the game a lot more fun. Dig into even more of the lore and history behind the World of Warcraft in WoW Insider's Guide to Warcraft Lore.