The Champions of Azeroth is a new neutral faction in Battle For Azeroth, granting players extra item levels to the Heart of Azeroth neck. Hitting Revered with this faction is a component of Azerothian Diplomat (a component of Battle for Azeroth Pathfinder, Part One). Exalted rewards Champions of Azeroth which counts towards 100 Exalted Reputations.
Starting in patch 8.1, players may now earn Paragon reputation with Champions of Azeroth. Paragon reputation allows players to earn reputation beyond Exalted, rewarding players with Champions of Azeroth Supplies for every 10.000 reputation afterwards. The cache contains extra Azerite, and random items. There is also a chance for the cache to contain Azerite Firework Launcher.
The Quartermaster is Magni Bronzebeard who can be found at (42.2, 44.2) in Silithus. Take a Silithus portal from your Zuldazar / Boralus hub to get here quickly.
Gaining reputation with Champions of Azeroth is relatively simple: Complete world quests associated with this faction on Zandalar and Kul'tiras. World Quests spawn at different times for max-level players that have completed Uniting Kul Tiras or Uniting Zandalar. Regardless of difficulty, world quests award a flat 75 reputation before buffs. During the World Quest Bonus Event in Battle For Azeroth, players get bonus reputation with the appropriate faction via Sign of the Emissary. All of these World Quests involve the player recovering Azerite from different sources including Miners, Elementals, and Rare Elites! The Azerite you recover goes directly into your Heart of Azeroth. These World Quests can spawn in any of the six BFA zones.
When you reach Friendly, Honored, and Revered Reputation levels with the Champions of Azeroth, a quest will unlock. On completion, each of these quests will grant you 15 bonus item levels to your Heart of Azeroth.
Upon reaching Friendly, head to Silithus and receive The Heart's Power and claim your 15 item levels to your Heart of Azeroth.
Upon reaching Honored, head back to Magni to pick up Unlocking the Heart's Potential and get 15 more item levels to your Heart of Azeroth.
Upon reaching Revered, head back to Magni to pick up The Chamber of Heart and get another 15 item levels to your Heart of Azeroth.
After completing the above 3 quests, Magni has a final quest called A Brother's Help to receive a final 10 item levels to your Heart of Azeroth.