WoWDB

Archiereus of Flame has the abilities of both Eternal Kilnmaster and Blazebound Chanter (except for  Fiery Charge and  Greater Pyroblast).

 Blazing Blow: This ability requires quick mobility, especially if Archiereus is augmented by the Eternal Kiln (more below). Depending on how well geared your character is, it will not one-shot you but still hurt very much.

 Cauterize: Interruptible. Although in the long term it is a negative return, it's still advised to prevent this yaungol from casting it.

 Conjure Eternal Kiln: The most threatening ability aside from the Flarecore Golem. When Eternal Kiln is summoned, Archiereus gains a buff from it called  Kilnfire. It increases his speed - movement, attack, and casting - and damage (physical and fire) by 50%. This will prove fatal if the summoned mob is not destroyed immediately.

 Conjure Flarecore Golem: Summons a Flarecore Golem with ~39mil HP that hits like a truck. More than one can be active for the duration of the fight, and it will despawn upon the death of the summoner. Must be kited.

 Fire Storm: This ability shoots out swirly stuff in random directions. It will not one-shot a person (unless modified by Kilnfire), but be nice to your healers - avoid standing where the swirly projectiles will land.