Sentinals
Not long after the Night Elf druids entered the Dreamways of Ysera's Emerald Dream, High Priestess of the Sisters of Elune, Tyrande Whisperwind, assembled a powerful fighting force from amongst her night elf sisters. The fearless, highly trained warrior women who pledged themselves to The World Tree's defense became known as the Sentinels. This period in history became known as the Long Vigil, and ended when the druids were awakened prior to the battle for Mount Hyjal.
In the defense against the Scourge, the Sentinels felt that their forces were not enough to keep the vile creatures off their sacred homeland. So they began their search for elite war champions of all species to aid them in battle. The Humans, Orcs, Furbolgs, Trolls and Faerie Dragons who joined them, all name themselves the vigilant Sentinel.