Aszune

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

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. The dragon 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 also 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, 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 figthing off the Naga forces, her runner got through the Pillars of Aszune to reach Malfurion Stormrage on Kalimdor. The name of the pillars implies that Aszune lived before the Great Sundering and was rather famous.

Quotes

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

Speculation
Nothing is known about Aszune beyond the information revealed in the above missions of Warcraft III. Her title suggests she might be related to Queen Azshara, but no information has been established. She makes no appearance in any document pertaining to the War of the Ancients, so whenever she was imprisoned, it was likely some time before the war, as no "princesses" or relations of Azshara would have gone undocumented afterward. Though, there are a few obscure highborne princes in World of Warcraft, such as Prince Tortheldrin and Prince Toreth. Her name appears to be somewhat similar to Queen Azshara's.