Originally Posted by
Flurryfang
Well, its hard to keep yourself short when it comes to one of the most active characters in all of Warcraft, but let me try.
She started out as a High Elf general. She was the leader of the defense of Quel'thalas when Arthas attack the land. She was killed by Arthas and later raised as a banshee - An undead witch. After having served in Arthas's undead army for some years, she took over her own part of the undead legion and named it The Forsaken. She only did this after Arthas had left for Northrend, where the LK were loosing his power over the undead. Because of the LK loosing grip of the undead around Lordaeron, Sylvanas took control of the eastern kingdom, including Undercity, after a few battles with some dreadlords.
She was now ruler of her own kingdom, and of her own people. Yet the world was still dangerous, especially with a strong new alliance being formed between men, dwarfs, Night Elfs and Gnomes, so she allied herself with The Horde, even though many horde members did not agree with this alliance. She promised that in return for her membership, she would bring the north of The Eastern Kingdoms, under Horde control. Her real reason for this alliance was not to keep her people safe, it was really to get help hunting down Arthas one day. That became possible when Arthas attacked Orgrimmar. The horde and alliance attacked Northrend and killed the LK. So now, with Arthas dead, like Maiev Shadowsong, needed to find new purpose in her life. She then really took the Queen titel serious and took her peoples need first. The first problem she had to deal with, was something that had plaqued the undead for a while. Since Sylvanas had taken control of her pack of undead, after Arthas left, she had not been able to recreate more people. This meant that her people was on a over continuing decline, never being able to produce more forsaken. That problem got solved, with the inclusion of the Val'kyr into The Forsaken. These undead angels, would raise the dead of lordaeron and give new "life" to the forsaken army. So now, with renewed strength after the Northrend expedition, she began making plans for her conquest of the northen region of the Eastern Kingdom.
This plan came to fold with the beginning of Cataclysm, where she lead her army through Silverpine Forrest and Hilsbrad Foothils, destroying most alliance forces under her boot. This war was pushed on by the new Warchief, Garrosh Hellscream. He showed little love for Silvanas and her undead people, and pushed them into the meatgrinder which was the Gilnean-Forsaken war. Sylvanas, after this war, began to show little love for Garrosh, which eventually led her to join the army of horde revolutionaries who laid siege to Orgrimmar. Garrosh was jailed, Sylvanas kept doing her stuff in the Northen Kingdoms and now we are at the start of Legion.
Sylvanas is really a woman with a tragic story. She hated the undead for what they did to her homeland of Quel'thalas, yet she became undead herself and even began to rule these unnatural people herself. She know that there is little love for The Forsaken, outside in the world, so she does her best to become an important part of the Horde, so important, that they would never dare throw them out of this family of missfits. To keep this spot, in the horde, she has done terrible things, like using plague and torturing people, but it has since Cata, only been done, so her people can feel safe inside this world, which don't really want them.
PS: Wups, ended up not being so short O.o