This service will get you the Antorus final boss – Argus killed in the Heroic mode. You will get an Kirin Tor Summoning Crystal (Violet Spellwing) mount and Ahead of the Curve: Argus the Unmaker.
You will also have a chance to get one of the BIS Pantheon Trinkets for your specialization, including the 3rd Legendary – Aman’Thul’s Vision (low chance), Pantheon’s Blessing (used to upgrade trinkets) or amazing transmogs: Scythe of the Unmaker (low chance both)
PREPARE FOR BFA
Becomes Feat of Strength (and impossible to get after the BFA pre-patch).