The official Warcraft story at Worldofwarcraft.com says that Tirisfal Glades was the landing place of the High Elves led by Dath’Remar Sunstrider after the Night Elves exiled them from Kalimdor. Taking that at starting point, there is a Grove west of Deathknell that is sealed off, as a potential placeholder. It can’t be accessed. However, it is a big area as you may see on the map to the right.
Speculation: If this grove is where the High Elves first created a settlement, whatever is underground within the mysterious grove could possibly be an Elemental—there are some elementals like Myzrael and the Princess Theradras ( mother of the Centaurs located in Maraudon ). Or whatever is uderground in this Tirisfal grove is related to the Old Gods. See what I mean in the story of The Founding of Quel’Thalas:
One of the Old gods killed by the Titans is in southern Darkshore. It is unknown if another dead Old god is in Tirisfal or not. Officially there are only five known Old gods. Three are imprisoned and chained beneath the surface of Azeroth. One has a Titan’s Glaive through its skull at Darkshore. And C’Thun in Ahn’Qiraj (Silithus).
A possibility for this Mysterious Grove in Western Tirisfal Glades could be also where Krasus lived. In Warcraft: Day of the Dragon novel, it says that the Elven-built Sanctum of Krasus was built upon a mysterious grove. Krasus was one of the Six Senior Archmage Leaders of the Kirin-Tor. Secretly, though, Krasus was no High Elf. He was secretly Korialstrasz the red dragon—the consort of Alexstrasza the Queen Dragon Aspect.
Korialstrasz shapeshifted into a High Elf and posed as one to infiltrate the High Elven and Human races, watching their magic development and evolution. As consort of the Queen Dragon of the Aspect of Life, he felt his sworn duty was to watch, guide and protect the lesser races.
You can read at Warcraft: Day of the Dragon—page 265, the following:
It is kinda long to type here but Krasus used this pool rare times. He would drink from its water to rejuvenate his strength. Any crafted object or cup would be rejected by the pool’s waters. Krasus had to use his hands to drink the waters.
I see a connection here …. that place west of Tirisfal could be the grove where the Citadel of Krasus is, which could also be the place the High elves first landed in when exiled.
The quote above says that an elf created the citadel (possibly Dath’Remar Sunstrider) over a ground older than the dragons … therefore that grove west of Deathknell could be where the high elves first landed in Tirisfal Glades and built the first settlement. Later, the High Elves became insane with the old whisperings coming from beneath the ground, and had to leave. The High Elves sailed off the coast of Tirisfal Glades, heading toward the north—where they found Quel’Thalas.
The pool could possibly be a Sunwell created by Dath’Remar—from one of the vials of Illidan. The high elves took with them “some” of the remaining 4 vials of water from the original Well of Eternity that Ilidan had before being imprisoned 10,000 years ago. Ilidan only used 3 vials in Hyjal before captured. This is mere speculation. The first and only Sunwell in the lore was created in Quel’Thalas by the Sunwell Grove. There is no mention in the official lore of a second Sunwell in Tirisfal Glades. So the interrogative remains: What is the origin of the pool beneath Krasus’ citadel? Is it Old god related or Titan related? Is Krasus’ citadel in the mysterious grove to the west of Tirisfal Glades? There is no further lore in any of the pocketbooks or RPG books revealing what is within the mysterious Grove of western Tirisfal Glades. However, something else to note is that Warcraft RPG: Magic and Mayhem says an interesting new lore few know about:
It seems Lady Sylvanas has more secrets than we thought. If these golems exist in Undercity, it is meant to be hidden knowledge from the Horde. One fan once theorized that Sylvanas might have struck a bargain secretly with the Old gods. This is not referenced anywhere in the lore. What is known of the Undead Forsaken is that they are creating toxins and a new plague behind the back of the Horde, and even tested a poison against one female Tauren at the Apothecary District in Undercity. Their intentions are clear. Whether Sylvanas stroke a bargain with the Old gods somehow is unknown, but it is fairly strange that there is no representation of the Undead Forsaken at the Ahn’Qiraj War Effort or Cenarion Hold ….
These 13 Golems have rich runes of an ancient undecipherable tongue and wear a strange iron-forged death mask. Could the origin of the 13 Golems have anything to do with the secret pool beneath Krasus’ Sanctum? Old gods or Titan-made? Take everything in this page with a grain of salt. It is speculation based on released info, not official lore.