The Aldor Reputation Quartermaster may be found at the Aldor Bank in the northern side of the Terrace of Light in Shattrath City. Quartermaster Endarin sells tradeskill-profession recipes and armor for honored, revered and exalted players. To gain Aldor reputation you should complete quests given by NPCs at the Aldor Rise on the northwestern side of Shattrath City. You may take the elevator to reach it.
There is a repeatable quest that increases Aldor reputation by turning-in Marks of Kil’jaeden up to 6000 Friendly. Then Marks of Sargeras starting Honored. The quest giver is Adyen the Lightwarden at the center of the Aldor Rise in Shattrath City.
Demons and Shadow Council also have a chance to drop Fel Armament. Keep them. Go to Ishanah (High Priestess of the Aldor) at the building in the center of Aldor Rise. She takes the Fel Armament and turns it into Holy Dust which is used instead of gold to buy inscriptions. The turn in of Fel Armament gives Aldor reputation. Shadow Labyrinth mobs drop it often.
Note: You get these marks from demons and Shadow Council anywhere in Outland, including dungeons such as Shadow Labyrinth. Demon locations: Legion Hold, Illidari Point and Warden’s Cage in Shadowmoon Valley; Forge Camp: Fear, Forge Camp: Hate and Twilight Ridge in western Nagrand; Forge Camp: Terror, Forge Camp: Wrath, Felstorm Point, Death’s Door, and Forge Camp: Anger in Blade’s Edge Mountains; and Forge Base: Oblivion, Forge Base: Gehenna in Netherstorm. You can find Aldor quests at the Inn of Area 52 (Netherstorm).