Seereth Stonebreak is a level 26 quest giver located west of Honor's Stand close to the entrance to Stonetalon Mountains, in the Horde-aligned territory of the Barrens.
She starts the following quests:
[18] The Elder Crone- [19] Goblin Invaders
[23] Shredding Machines
See List of the Barrens NPCs.