<Mage Tover Warrior Arms> What i'm doing wrong?

I link here the replay, seriously the shadow have SOO MUCH HP I don’t see how i’m supposed to kill it. even with trying different drum timing it’s not enough.

I don’t understand because I did this damn challenge during Legion on EU, and I didn’t needed a drum, so … WHY this boss is so damn tanky ???

i use crusader enhan, azeroth heart, and wrathion cloak btw. and a weapon 46 ilvl in memories.

The one advise I can give you from watching the video, is when he starts channeling the add spell, wait until there’s 1 to 2 seconds left (which ever you feel comfortable) and leap away, that way you can get more dps on him, at least that’s what got me the kill.

i’ll try it