The Hydraxian Waterlords are the sworn enemies of Ragnaros of Molten Core.

"Reputation rewarded for killing mobs will no longer automatically deprecate. This means trivial mobs will continue to give out their full amounts of reputation on kill for the majority of cases in the game (level 70 creatures in Stratholme, for example, will continue to award the full amount of rep to level 80 players seeking to boost their Argent Dawn faction)." Patch 3.08 Notes.

Molten Core Trash Mob Reputation

1. Ancient Core Hounds reward 20 reputation until revered.
2. Firelords reward 20 reputation until revered.
3. Lava Packs reward 40 reputation until revered.
4. Lava Surgers reward 20 reputation until revered.
5. Molten Destroyers reward 40 reputation until revered.
6. Molten Giants reward 20 reputation until revered.

Molten Core Boss Reputation

1. Baron Geddon rewards 100 reputation until exalted.
2. Garr rewards 100 reputation until exalted.
3. Gehennas rewards 100 reputation until exalted.
4. Golemagg the Incinerator rewards 150 reputation through exalted.
5. Lucifron rewards 100 reputation until exalted.
6. Magmadar rewards 100 reputation until exalted.
7. Ragnaros rewards 200 reputation through exalted.
8. Shazzrah rewards 100 reputation until exalted.
9. Sulfuron Harbinger rewards 100 reputation until exalted.

Others who give Hydraxian Waterlord Reputation

1. Desert Rumblers in Silithus reward 5 reputation until honored.
2. Dust Stormers in Silithus reward 5 reputation until honored.
3. Greater Obsidian Elementals in the Burning Steppes reward 5 reputation until honored.
4. Huricanian a rare spawn in Silithus rewards 25 reputation until revered.
5. Lord Incendius in Blackrock Depths rewards 15 reputation until revered.
6. Pyroguard Emberseer in Upper Blackrock Spire rewards 50 reputation until revered.