Since the Cataclysm, the lake dragonkin have disappeared, likely due to their fear of Deathwing. Spirits now inhabit the lake, and a phased quest allows players to see the invasion of the Burning Legion 10,000 years ago.
Malynea Skyreaver provides insight into the lake's origins:
Player choice: Tell me about the nearby ruins.
Are you familiar with the War of the Ancients, <Name>? That is what we call the period of time 10,000 years ago, when the demons of the Burning Legion first breached the realm of Azeroth and attempted to devour this entire world as they have countless others. The ancient capitol of Azshara, a city that once dominated this landscape, was ground zero for the invasion. The ancient wreckage you'll find scattered throughout the area stands in broken testament to the egotism of our forebears.
Player choice: What are you doing here?
My concern for the moment is with the ruins that surround Lake Mennar, to our east. Thousands of years ago the Mennar Academy was among the first to study the arcane arts. It was a beautiful terraced structure built in a ring around a tranquil lake, a place of quiet contemplation and focused study. It was there that my ancestors first discovered the potential of the magical energies seeping from the Well of Eternity.
I'm sorry - is this all too much to take in? I've immersed myself in arcane history for several decades now, I forget that others do not share my passion.
Player choice: No, please go on.
Suffice it to say that the academy was cautious in its application of these new-found powers - what few writings remain indicate that the mages there worried about arcane addiction, a problem my race suffers from to this day.
This restraint put the mages of Mennar in opposition to Queen Azshara and her highborne lackeys, who sought ever greater power with wild abandon, throwing caution to the wind and delving into ever more dangerous applications of the arts.
Player choice: What happened to the mages?
By the time the Burning Legion began its assault, the mages at the Mennar Academy had fallen far from the Queen's graces. They would've been a powerful asset in the war to come, but they refused to fall back when the of the city fell.
Instead of regrouping outside the city to join in the counter-assault, they stayed behind, erecting magical barriers and turning their once quiet home into a fortress. Refugees streamed to the Mennar Academy in the first terrible days of the Invasion, and survivors tallied to mount a defense.
Player choice: Were they able to hold out?
Hold out? Against a full frontal assault from the legion's vanguard? Not likely!
No, history doesn't record what happened next... for there were no survivors. The raging demons left little more than the ruins you see today, and the secrets of the academy lay buried under the soil of Azshara.
Player choice: And we're going to dig them up.
I like the way you think, <race>!
Until recently, the latent magical energies of the academy grounds attracted the attention of the Blue Dragonflight, and I wasn't able to study them. The attention of the dragons is now elsewhere, but a worse threat is in the making - these little green brutes want to level the ruins to make way for a fuel depot! Knowledge lost for ten thousand years is days away from being lost forever. We've got to act fast.
- Patch 4.0.3a (2010-11-23): Dragonkin removed, spirits added.