You forgot his &quot;Nether Burn&quot; ability:

[quote:fa3784401e][b:fa3784401e]Nether Burn[/b:fa3784401e]: Aura type spell, deals 1200 shadow damage every 5 sec, affected by line of sight. This damage is resistible, so shadow resist buffs beforehand can negate much of it. Only active during Portal phase.[/quote:fa3784401e]

From WoW Wiki.