1. Defeat 15 Master Tamers on Kul Tiras or Zandalar with a team of all level 25 Undead pets
2. You should have at least 10 appointed fully leveled Undead pets with which we can do the achievement.
3. You need to provide your account.
4. Your character's level should be 120.
5. ETA: 1-2 Weeks.