The Ashtongue Deathsworn are a secret Broken subgroup of the Ashtongue tribe, under the command of the Elder Sage Akama. They were secretly planning to depose Illidan Stormrage as the master of the Black Temple.
Upon talking to Sanoru, players will become neutral with the Ashtongue Deathsworn. Reputation can be gained with the Deathsworn by completing some quest chains. You also gain rep by killing the mobs inside the Black Temple. A full clear of the Black Temple yields approximately 7750+ reputation, whereas a repeatable clearing of all the trash prior to the first boss, High Warlord Naj'entus, will yield approximately 570+ reputation per run.
A quest chain that leads to Akama exists. It starts from either the Aldor Base, Altar of Sha'tar, or the Scryers base, Sanctum of the Stars, depending on your affiliation.
After you complete that chain, Akama begins another which eventually takes you to The Arcatraz.
After this chain, Akama sends you to Shattrath with a message for A'dal in the quest Akama's Promise (1000 reputation with Ashtongue Deathsworn and The Sha'tar). At this point, non-humans will have 1925 (Neutral) reputation with the faction.
Once the above quests are completed upon slaying Fathom Lord Karathress in Serpentshrine Cavern, an NPC named Seer Olum will spawn; talking to him will begin the following quest chain: