Avenge Me!

This Achievement seems bugged. I've tried this over a dozen times now. 10 stacks on an Elite, no problem, kill elite, Achievement will not complete. This seems to be broken, anyone else with this issue after Dark Heart patch?

As a mage, I found this fairly easy to solo.

I found this big room with two elites fighting eachother in the middle and plenty of trash around them as spectators. I used invisibility to bypass the guards at the entrance and took my place amongst the spectators. I cast polymorph on the one elite and killed the other. Then I just pulled the trash to the polymorphed elite and killed them nearby, adding 1 stack of Vengeance for every mob I killed. After I had killed 10 trash mobs close to the polymorphed sheep, and the sheep had his 10 stacks, I set up my cooldowns and opened up, dropping him well before he could ever reach me.

Hope this helps some other people! Good luck :)

This achievement is tricky to do solo because the elites continually grow in power on their own in addition to the vengeance buffs you're stacking them. Fortunately for Priests, we have a trick that can make this soloable with some effort.

1 - Reset Torghast with the Avenger torment until you find one with an undead elite not too far away from other minions.
2 - Chop the undead elite down to 10k or so health.
3 - Cast Shackle Undead on the undead elite.
4 - Start dragging over minions and killing them near the shackled elite. Don't use any area of effect abilities that might break the shackle.
5 - Refresh Shackle Undead after each kill or two so that the elite's shackle doesn't expire.
6 - Once the Undead Elite has 10 stacks, nuke him down. (Shadowfiend + Fade can buy you an extra second or two, although it probably won't be necessary).

I had to refresh the instance 4-5 times before I found a suitable elite (most I found were humanoid). But once I found him it was just a matter of clearing a safe area to fight then running through this strat. All in all, not difficult.