Sif was the wife of Thorim. She was murdered by Loken, who tricked Thorim into believing that it had been the work of Arngrim, the king of the ice giants. This caused Thorim to turn against his allies, then lapse into a long depression.
Yogg-Saron created an illusion of Sif to corrupt Thorim in Ulduar. She has the model of a female frost vrykul. Thorim's hard mode requires that he be defeated in her presence, she will attack the raid with heavy frost damage spells. After the mortal champion players break Thorim of his nightmarish controlled state, Sif will transform into a tentacle of Yogg-Saron and disperse through the ground.
In life it was possible that Sif was a Hyldnir-born Vrykul that won the Hyldsmeet thus she became Thorim's beloved wife and side by side ruler. The first half of Hyldnir territory is called Sifreldar Village and could possibly be named in her honor from her death or for winning the Hyldsmeet.
Sif will cast spells that hit targets for high amounts of frost damage, she will also teleport around the arena into random spots, she cannot be damaged or targeted and is considered an obstacle for the raid encounter.
- Touch of Dominion: Subjugates the target to the will of Yogg-Saron, weakening it yet conferring a subtle control. Sif channels this on Thorim which acts as the hard mode goal timer.
- Melee: Sif will hit with her staff for 1k damage.
- Frostbolt Volley: Throws a volley of frostbolts to nearby enemies, inflicting them for 11250 to 13750 frost damage and reducing their movement speed by 50% for 4 seconds.
- Frost Nova: Causes a sweep of ice to immobilize nearby players for 6 seconds, and causes 14138 to 15862 frost damage, 2.5 second cast.
- Blizzard: Causes a shower of frost and ice to rain down and slowly move around the arena, players hit will be inflicted with 3.2k - 4.2k frost damage and have their movement speed slowed by 65% by remaining in the blizzard.
- Thorim, my lord, why else would these invaders have come into your sanctum but to slay you? They must be stopped!
Hard Mode Reached:
- Impossible! Lord Thorim, I will bring your foes a frigid death!
- Patch 3.1.1 (2009-04-21): (Undocumented changes)
- Sif's Frostbolt Volley now inflicts 11250 to 13750 damage.
- Sif's Frost Nova now inflicts 14138 to 15862 damage.
Frostbolt Volley up from 9000 to 11000, Frost Nova up from 9425 to 10575.