This unusual monument is surrounded by a small lake. While it was once a night elf holy place, the area is now under the control of the Twilight’s Hammer. They believe the statue is some sort of divine corpse — the remains of an Old God. The term "Master’s Glaive" refers to part of the monument — the sword embedded in the skull.
The shell has holes where presumably eyes should be, and tentacles are draped around the area, giving it an appearance similar to a kraken. The Twilight's Hammer have chosen it as a location for one of their dark altars, and have a small camp here. Therylune can also be found here.
CataclysmThis section concerns content exclusive to Cataclysm.
In the expansion World of Warcraft: Cataclysm, The Master's Glaive has been transformed by the Twilight Hammer into a massive excavation site. Their excavations have revealed that the nautilus-like object was actually the skull and upper-torso of a massive minion of the Old Gods named Soggoth the Slitherer. A similiar site exists in Twilight Highlands, known as the Husk of Sor'getha.
Battle for AzerothThis section concerns content exclusive to Battle for Azeroth.
It is confusing why the titans would have impaled a minion of the Old Gods and left such powerful a weapon in its dead corpse. Some theorize that the sword in its remains prevents it from regenerating and putting Azeroth in danger once again. The Twilight's Hammer are worshiping the Old God's remains, and perhaps they are trying to reawaken it by removing the sword from the creature.