training Realm First! Obsidian Slayer (25 players)
The tactic of this achievement is that, you must be the first group with 25 people to go to The Obsidian Sanctum and kill the boss Sartharion there , and if you succeed in doing this, you will receive the Obsidian Slayer title at the end.
Below you can see how to get this achievement.
.
.
