The Grandmaster of Outland seemed pretty challenging at first, but compared to the Pandaria tamers, he’s a pushover. Still, he’s worth doing for the 2k+ xp and chance at a battle-stone. If you forgot where he is, check the map.
Pets and Abilities to use:
Emperor Crab (level 25) with Surge, Renewing Mists, and Whirlpool
Mechanical Pandaren Dragonling (level 25) with Breath, Flyby, and Bombing Run
Use the crab to defeat the elemental; use MechPanDrag for the wyrmling. Either can defeat his dragon.
Depending on which pet you’re carrying, you may want to lead with him so he soaks Immolate from Jadefire, or bring him in for Netherbite because he is so weak. Either way, a crab makes quick work of the elemental, and MechPanDrag is well suited against both Arcanus and Netherbite; being mechanical, he will take reduced damage from the magic attacks they throw at you. If for some reason he manages to die twice, you can finish off Netherbite with your crab.
Notes on pet selection:
A lot of different teams can defeat Antari easily. This is just the one I like to use. A good snail or crocolisk can be substituted for the crab, and a fluxfire feline can stand in for the dragonling. Whatever you have lying around, really. As long as you don’t try to pit aquatic damage against Arcanus (who is strong against it), let MechPanDrag stand toe-to-toe with the elemental, or bring in a Flyer, you should be fine.