Demonslayer of Tanaan

There are easier demons to slay besides those mo fo's up at the throne. Off to the side of the fel forge where the ooze also are you'll find packs of threes of those imps. It is so close to Vol'mar (not sure where alliance camp is yet) and they respawn quickly. You can do this daily in 5 minutes. Beats that awful throne with the fel buff and huge hp on the mobs.

Up a bit by the felblight, the fel touched wolves also count as a demon, and you can collect the fangs and claws for the daily.

Just find packs of imps to the south of the Throne of Kil'jaeden; each one counts and will help you quickly and easily get the necessary credit.

EDIT 7/6: A recent patch allowed the zone's Felbound Wolves to also count towards quest credit.

There is a small area with nothing major except Corrupted Elemental Flame(195K) and Fel Ooze (78K). Imps show up every few minutes running around in groups of 3. It's a small area located at 54,44, but easy to farm and you can quickly and easily AOE the imps down. It's also close to Vol'mar so if you attract an unwanted mob or a pesky allie, you can run for cover quickly.

There is another place just to the northeast of Vol'mar at 64,38 that yields a population of Felbound Wolf (88K) which are easy to kill, in groups of 1 to 5 and count as demons. They also yield teeth of you are doing Tooth and Claw at the same time.