The Silence When You Speak to Me (20)
Listen to all of Master Ordan's conversations in the Pandemonium Fortress
Bringer of Order (20)
Complete Act V with a Necromancer
These achievements will be best completed together. Personally, I did this on Normal, using the Metabolism rune on Blood Rush to grant two charges of your “teleport”. Add an In Geom to the cube for an added bonus, but it is not necessary. There is also no need to do the entire campaign. All you need is someone who has completed the campaign and have them start the game at the beginning of Act 5. If you have done this on another character, have someone join your game then log out to switch to your necromancer. As you complete the act, you will see Master Ordan - just make sure you listen to all the conversations. You will run into him twice.
NOTE: If you are partied up for this, only one person can get credit for the first conversation when you encounter Master Ordan.
NOTE: Make sure you listen to the Enchantress’ quests, as you unlock her special zone - which is notorious for its pools of reflection (up to 3 per go, stacks to 10). Helps gain paragon quickly if you’re low - just don’t die!!
Serve the Balance (20)
Reach level 70 with the Necromancer
Self-explanatory. Get a power-level and you’re done!
Bone Skewer (20)
Damage 40 enemies with Bone Spear in 3 seconds
The best place to achieve this is in a cow level, or in the Ruins of Corvus (act 5). Certain walls will have a horde of scarabs come over it, giving you easy targets. You don’t have to kill them, just damage them. Place the game on Torment 1-3, while using the Moribund Gauntlets and Command Golem with the Flesh Golem Rune. The Moribund Gauntlets make your golem spawn a corpse every second, meaning you shouldn’t have a shortage after using the Command Golem to spawn the initial 8 corpses - just use it in a nearby area where there are no mobs. The best ability to use to damage the enemies is Bone Spear, Ricochet. When you are all set, fire at will.
What is Dead Can Sometimes Die (20)
Kill 1,000 Undead enemies with corpses
Game of Bones (20)
Use Bone Armor to rip the bones from the Skeleton King]
These achievement are fairly easy, and easy to pair together. I used Corpse Explosion with the Bloody Mess rune. I found it easiest to go through most of the Act 1 zones, since they have the highest concentration of undead. Once again, place your game on Normal. Have any Bone Armor on your bar. Just do not activate it until you are on Leoric (and use it AFTER he becomes attackable). I started in the Cemetery of the Forsaken, and ran through the Cathedral levels, ending on Leoric. Briarthorn Cemetery also has a great concentration of undead. Repeat zones if necessary.
Curse Your Enthusiasm (20)
Kill 5,000 cursed enemies
This achievement is best done with the Frailty curse with the Transmittable rune. Just run around high-density zones with your curse active. Act 3 zones have a lot of these, especially on the path to Azmodan.
Terror in the Blood (25)
While under 10% life and fighting Diablo, use an ability that costs health and then defeat him
Self Controlled (25)
Kill your own Shadow Clone with Simulacrum during the Diablo encounter
Do this achievement on Normal, using the Death Nova with the Blood Nova rune. The idea is, you use it 9 times in rapid succession around Diablo, then damage him. Ta-da. Also, make sure you have Simulacrum ability on your bar, I did it with no rune. When you enter the Shadow Realm, aka phase 2, just kite diablo without damaging him (aka do not use bone armor or pets, anything with a passive AOE). When your clone spawns and becomes attackable, use the ability. You should get it, but it may take a few tries as I have noticed with others.
Skeleton Crew (25)
Kill 500 elite (champion, rare, or unique) enemies with Command Skeletons minions
This one is by far the hardest of the achievements. I am currently working on this on the highest torment I can. Use the Command Skeletons with the Frenzy rune. Do not use any other pets, curses, or abilities that have passive AOE. Land of the Dead with the Frozen Lands rune is OK. Pair this with the ring Krysbin’s Sentence and the Jesseth’s Arms set (scythe and shield), and your skeletons should dispatch anything pretty quickly. The benefit with the Jesseth’s Arms set is the skeletons continue to activate on nearby enemies, and spread out on across the pack with each cast of Command Skeletons. This makes it easier to get credit for an entire blue pack. There is currently something going on that makes the game slow to update the progress, and sometimes doesn’t even credit at all. So keep plugging away and you’ll eventually get it. Greater Rifts are perfect for getting this done.
****NOTE**** Some people have been reporting that the Jesseth's Arms is providing complications for credit to elite kills.
And when all that is done...