You can earn the Mists of Pandaria Achievement Empowered Spiritualist pre Mists of Pandaria.
Taken from Wowhead:
You can get this achievement in the bossfight of Thalnos the Soulrender, the first boss of the Scarlet Cathedral.
The keypoint to get this achievement is in Thalnos ability "Summon empowered spirit". It will (of course) summon an empowered spirit who tries to reach the closest corpse of a crusader. Normally your group would try to kill it but if you want to get this achievement simply ignore the spirit. When the spirit reaches the corpse he will possess the body and will arise him as an empowered zombie - the objectives of this achievement. These zombies have much health (and are nearly unkillable because of that) and deal a lot of meleedamage to your tank. You have to wait until there are three of them, then finish the boss to obtain the achievement.
Video: Not mine video!
Don't forget to: Scarlet Halls: Empowered Spiritualist 5.0.4 - YouTube
Edit: Its a repost, thanks to gero321. Let this Thread die and go to the original:
http://www.ownedcore.com/forums/worl...ritualist.html (Easy 10 AP: Empowered Spiritualist)