Aszune

Aszune was a night elf princess who, long ago, mocked the Oracle's wisdom. As punishment, she was transformed into living stone. Only the retrieval of her gemstone heart could end the curse.

Background
Thrall happened upon the statue in the caverns of Stonetalon Peak during the Third War. The statue's magic created an impassable barrier, and the voice of Aszune spoke in Thrall's mind. The imprisoned spirit told him that she would not allow passage to the Oracle's domicile until her heart was returned to her.

Thrall found the heart in the possession of a red dragon who was under attack and nearly killed by harpies that were after its treasure. Thrall retrieved the dragon's magical amulet and gave it to Aszune. With this act, he ended the curse, allowing her spirit rest, and the barrier that denied him access to the Oracle was lowered.

The essence of Aszune's heart had come, through unknown means, into the hands of the Kirin Tor of Dalaran (after the city was destroyed too, it seems). They locked it away in the dungeons beneath the city, the Violet Hold, where it was eventually found by Lady Vashj.

The Pillars of Aszune is a series of arcs on the Broken Isles that lead to the open sea. When Maiev Shadowsong was fighting off the Naga forces, her runner got through the Pillars of Aszune to reach Malfurion Stormrage on Kalimdor. The name of the pillars might imply that Aszune lived before the Great Sundering and was rather famous. It might also refer to the region of Azsuna, not far from them.

Quotes

 * "I am Aszune, ancient princess of the Moon Children. None may pass until my heart is returned to me."

Speculation

 * As a princess, she was very likely a Highborne.
 * Aszune's name resembles Azsuna, hinting at a possible connection between the two. That area was ruled over by the Highborne named Prince Farondis. The only known depiction of Aszune was found in the bowels of Stonetalon Peak, which would have been located to the far west of Zin-Azshari and the Well of Eternity, while Azsuna and the rest of what is now the Broken Isles was located north-east of the capital. However, there was also a location known as the Pillars of Aszune near the Broken Isles in The Frozen Throne. As such, she may have been Azsuna's ruler before Farondis.