Ranger General of Silvermoon, Dark Lady, Banshee Queen of the Forsaken, now Warchief of the Horde—having suffered great losses throughout her life, and undeath, continues to press forward to preserve herself and her people.
In Warbringers: Sylvanas, we witness the final moments of her mortal life. Sworn to protect the people of Quel’thalas as the commander of its military, Sylvanas used all her prowess to defend her lands from the Horde in the Second War. The Third War saw another attack on Quel’thalas, this time by the fallen Prince of Lordaeron, now death knight, Arthas Menethil and his undead scourge in service of the Lich King. Slowly but surely the High Elves were pushed back to Silvermoon, their last hope lying in the magical enchantments securing the gates to the city—only to be betrayed by one of their own. Sylvanas falls in battle at the hand of Arthas. Refused a swift death, he turns her into a banshee, bound to his will—forced to watch the destruction of the Sunwell, used to resurrect the mage Kel’thuzad into a Lich, and assist in the sacking what remained of Lordaeron.
Slowly, Arthas’s powers begin to diminish—Sylvanas and her banshees regain control of themselves. Driven by vengeance, she reluctantly agrees to work with dreadlords of the Burning Legion in order to take out Arthas and recover her body. Refusing to grant him a swift death, just as he denied hers, Sylvanas’s plans are foiled at the last minute by Kel’thuzad coming to the rescue—whisking Arthas away to Northrend to fuse with the Lich King.
With the return to her corporeal form, possession of the fallen capital of Lordaeron, and the former scourge, dubbed Forsaken, at her command—Sylvanas begins preparations once again to seek out Arthas to have her vengeance, founding the Royal Apothecary Society to develop a plague to destroy him and his undead Scourge. Seeking alliances, the Forsaken are rejected by all but Thrall, Warchief of the Horde. Later, Sylvanas brokers entry of the Sin’dorei—surviving members of Quel’thalas, also known as Blood Elves—into the ranks of the Horde.
After attacks on Orgrimmar by the Scourge, the Horde marches on Northrend to defeat the Lich King. Betrayed by Grand Apothecary Putress at the Wrathgate, the plague is unleashed upon the Scourge and the living, Alliance and Horde alike. Victory is won over Arthas, but there must always be a Lich King. Bolvar Fordragon, slain at the Wrathgate, takes up the mantle as Lich King, jailor of the damned.
Sylvanas travels to the frozen throne at the peak of Icecrown Citadel to gaze upon what remained of Arthas Menethil. Realizing a Lich King is still seated on the Frozen Throne turns her victory into a hollow one. She turns to the edge of the platform, having earlier confirmed the saronite spike below would obliterate her body, as the fall alone would not kill her.
Nine Val’kyr, transformed battle maidens of the Vrykul, last of their kind and slaves of the Lich King, witness Sylvanas throw herself off the precipice of the frozen throne. Showing her visions of the fate of the Forsaken in her absence combined with the agony she felt upon leaving her mortal coil, the Val’kyr convince Sylvanas to forge a pact—by binding their souls to Sylvanas, they escape the clutches of the Lich King, and save her from the pain and anguish she felt in the endless void. With the pact invoked, the leader of the Val’kyr, Annhylde the Caller took the place of Sylvanas in the void. As long as the remaining eight Val’kyr live—so would Sylvanas.
Upon her return from Northrend, Sylvanas meets up with now-Warchief Garrosh Hellscream, who has ordered the Forsaken to lay siege to the walled city of Gilneas. With newfound resolve to protect her people, Sylvanas refuses to further assist at Gilneas unless she can go about it her way. With her Val’kyr in tow, Sylvanas takes the city and, with the new-found power of her Val’kyr, raises fallen enemies into new Forsaken. This is a groundbreaking discovery, as the Forsaken have no means to reproduce.
After the defeat of Garrosh Hellscream during the Siege of Orgrimmar, leadership of the Horde is passed to Vol’jin, Troll Chieftain of the Darkspear tribe. Unfortunately, his reign was short-lived as he was cut down by the Legion at the battle for the Broken Shore. With his dying breath, he names Sylvanas as his successor, the new Warchief of the Horde.
Through numerous battles and personal endeavors, Sylvanas is left with three remaining Val’kyr. The most recent sacrificed to empower her champion–Nathanos Blightcaller, the only human to ever join the Rangers of Silvermoon and has served her, even in death, since before the Second War–in order to better aid her in the fight against the Legion. Sensing her fate drawing ever closer, travels to Stormheim. By making a pact with Helya, ruler of the underworld, Sylvanas gains possession of the Soulcage, a magical lantern. With the lantern in hand, she seeks to subjugate the goddess of the Val’kyr, Eyir, in order to create more Val’kyr, presumably to prolong her life indefinitely. If successful, perhaps this will also secure a stable future for the Forsaken.
While trying to force the will of Eyir, Sylvanas is interrupted by Genn Greymane. As king of Gilneas, he has sought her death since the battle that destroyed his city, where his son died protecting him from her poisoned arrows. Despite suffering major injuries in the fight, he manages to take the lantern from her and smashes it to pieces, thus ruining any hope she had at immortality.
With the defeat of Sargeras and the Burning Legion and the newfound information on the powerful substance, Azerite, Sylvanas seeks to control the precious resource and stop the Alliance from obtaining it. Her eyes turn to Teldrassil, seeking occupation of the Night Elven city, so as to slow Alliance access to the Azerite. At the last moment, as depicted in Warbringers, she chooses to burn the city to the ground, slaughtering many of its citizens. This massive act of aggression leads to the Alliance marching on the Undercity.