The elusive Elven Ranger known as Alleria learned of the devastation the Horde could bring as she searched for the remains of her family amongst the ashes of the once glorious Quel'thalas. Her all-consuming hatred for the Orcs led her to Azeroth where she leads an elite cadre of Rangers to hunt down the remaining Orc renegades of the Bleeding Hollow clan.[1]
Alleria is a hero with much higher stats than a normal Elven Ranger. She does not, however, benefit from Ranger upgrades.
She is one of the most useful heroes, as her long range allows her to attack enemy ships and Guard Towers from beyond their range.
She is introduced in the first Beyond the Dark Portal Alliance campaign mission, Alleria's Journey, and is also available in the mission Deathwing and then the finalthreemissions of the campaign. Her survival is a victory condition in all missions except the last. Alleria also appears as an enemy in the final mission of the Horde campaign.
Her portrait and sprite appear with different colors: in the missions Alleria's Journey, Siege of Vanguard and Dance of the Laughing Skull she is red, in the missions Deathwing and The Bitter Taste of Victory she is orange, in the final mission of the Horde campaign she is blue.
Trivia
She is not actually given the surname "Windrunner" in the game. Her sibling relationship with Vereesa from the Day of the Dragon and Sylvanas from Warcraft III was established only in vanilla World of Warcraft.