Buff up with shadow resistance / absorption before the fight!
Stay out of the blight when Sylvanas ascends towards the sky. You'll get hit by some insane DoT-dmg and 50,000 more shadow damage when she lands, as well as knocking you back.
Sylvanas uses four spells that does heavy shadow damage. Some of them are AoE. (See the list of abilities at the bottom of the page if you're especially interested.) Because of this you need to protect yourself from shadow damage as much as possible.
Sylvanas will once again ascend towards the sky and pull you towards her. You'll get bonded with a risen ghoul. Kill the Ghoul to break the bond, and do it as quickly as possible. Not only will everyone who cross the link lose heavy damage, but when the ghouls reach Sylvanas the whole group will lose 300,000 damage each if they are within 10 yards of Sylvanas reach
Echo of Sylvanas' Abilities
Shriek of the Highborne: Sylvanas shrieks with anguish, inflicting 50000 Shadow damage to a random enemy and decreasing their movement speed by -50% for 30 sec
Black Arrow: Sylvanas fires an explosive black arrow, dealing 50000 Shadow damage to a random enemy and their surrounding allies within 10 yards.
Unholy Shot: Sylvanas fires a volley of missiles at an enemy and its nearby allies, striking up to 3 targets for 50000 Shadow damage.
Blighted Arrows: Sylvanas blights the ground beneath an enemy and leaps towards the sky. The blight deals 35000 damage every 0.85 seconds and snares enemies caught within. At the peak of her jump, she fires a volley of deadly arrows at the blighted ground, dealing 50000 Shadow damage to those who remain in the blight, knocking them back.
The Calling of the Highborne: Sylvanas ascends towards the sky, pulling enemies towards her. Her calling rouses the dead nearby, who burst from the ground and form a dark bond. Players that cross this link will take 25000 Shadow damage initially, and for every second they stand in the shadows. They charge mindlessly towards Sylvanas, awaiting her sacrifice. The ritual of sacrifice deals 300000 damage to players within 10 yards of her. Defeating a ghoul will break the bond.
