MECHA-JARAXXUS Boss Guide for Trial by Felfire

This boss uses a deck of all of the 'Prime' minions from the Ashes of Outland expansion, such as Zixor, Apex Predator and Astromancer Solarian, in addition to a mix of strong Demons and Warlock spells. Additionally, the boss uses the Of Fel and Hatred Hero Power and will start with a Dormant Hatred Reactor and Fel Reactor on the board that will awaken after 3 turns.

In this encounter, you will be using a deck comprised of standard Demon Hunter minions, spells, and weapons as seen in previous encounters in addition to a few additional AoE cards like Immolation Aura and Altruis the Outcast. After your mulligan, you will also have Shalja, Demon Hunter, Karnuk, Demon Hunter, and Sklibb, Demon Hunter added to your deck.

In your mulligan you should look for cards that will help you deal with one, ideally both, of the reactors when they revive on turn 4 of the fight, such as Immolation Aura or Twin Slice. Aside from keeping a tech card for this reason, the rest of your mulligan can be used to look for strong minions for Turns 1, 2, and 3.

For the duration of the fight, your highest priority should always be controlling the board. You should always try to prepare in advance to ensure you can kill both reactors when they spawn, ideally from hand. If you find yourself in a situation where you can only kill one of the reactors, you should always make killing the Hatred Reactor your highest priority. If unchecked, the buffs it gives to enemy minions can snowball out of control quickly and put you in a position where you are unable to regain control of the board. After you keep the reactors in check, you should be able to comfortably grind down the boss due to its mediocre deck.