Heroic Harjatan is much, much harder than it looks.

The biggest difficulty is handling tank stacks, as they rise rapidly and deal enormous amounts of damage (for a Mage at least).

The second difficulty is Unchecked Rage, as the frontal cone will oneshot you once the boss reaches a few stacks of Enraged. Fortunately, the frontal cone has a 30y range, meaning that a single Blink cast while moving is just enough to get out of range. There is also a smaller, unavoidable damage that can mostly be ignored.

Glacial Insulation and Mirror Images are mandatory to pass this boss. Be careful, that means you must manage your GCD for Blink !

I pull with precast Mirror Image to ignore the first 40s of the fight.

Music :

Meizong & Yeeflex - Reaching Halo
https://www.youtube.com/watch?v=iufwV...

Enjoy :)