Sylvanas Windrunner was born a High Elf as the middle sister of the older Alleria and younger Vereesa Windrunner, she also had two brothers one who's name remains unknown and one called Lirath, Sylvanas eventually joined the rangers were she rose to the rank of Ranger-General, leading all military forces of Quel'thalas.
During the Third War, the Death Knight Arthas Menethil rallied the Scourge in the name of the Lich King and invaded Quel'thalas. Sylvanas made her last stand against the former prince himself but was ultimately defeated and raised to undeath to serve as one of his lieutenants.
Rebellion and forming the Forsaken
Not long after, the Lich King's control over the Scourge weakened, allowing Sylvanas and many undead to break free of his control. Sylvanas became the leader of the fledgling nation of undead fighters dubbed the Forsaken. Under her leadership, the Forsaken took over parts of Tirisfal Glades as well as the Plaguelands but remained in constant fighting with Arthas and the Scourge.
Eventually, Arthas was recalled to the Frozen Throne by the Lich King and Sylvanas rallied the Forsaken to secure control over Lordaeron. Having finally won revenge against the Scourge, Sylvanas found new allies within the Horde, now led by Warchief Thrall.
Second war against the Scourge
Years later, Arthas reawakened as the new Lich King, having remained in a comatose state to recuperate. Sylvanas and many other leaders of the Horde took the fight to Northrend and confront the Scourge once and for all.
After a long second conflict with the Scourge, the combined military might of the Alliance, the Horde, and the Argent Crusade finally struck the Frozen Throne and slew Arthas. Sylvanas, not satisfied without seeing Arthas' corpse, traveled to the ruins of Icecrown alone. There, she discovered that a comatose Bolvar Fordragon had taken up the Helm of Domination: although Arthas was dead, the Lich King were not.
This character was created by Blizzard Entertainment for the Warcraft game series and has also appeared in various Warcraft comic books.
Warcraft 3: Reign Of Chaos
Warcraft 3: The Frozen Throne
World Of Warcraft + Expansions
Heroes of the Storm