Obsidian Slayer is the reward for completing the achievement , being the first on a realm to slay Sartharion in the Obsidian Sanctum on heroic difficulty. While many of the "Realm First!" achievements were removed in beta, the realm first kills for Obsidian Sanctum and Naxxramas were preserved.
Realm First Feats of StrengthThe title precedes the character's name, in the following format:
- Obsidian Slayer <name>