Build Guide
Simple build for generating Essence as fast as possible to maintain 4 maximum Essence Singularity runed Skeletal Mages at all times, thus getting full benefit from the hotfix version of Bones of Rathma. Since you are shitting out Health Globes and Decrepify is reducing the damage all monsters do by 30% to your entire party (not just you) it makes a pretty decent group build with non-Necromancer classes.
While this build might change by the time the next Season starts, nothing is going to top this for damage or clear speed on Necro until that happens (Inarius is being nerfed at the same time this set is being massively buffed).
There isn't a lot to explain, walk up to a pack, curse them with Decrepify to trigger Dayntee's Binding, send your Command Skeletons at them to trigger the Jesseth Arms set bonus, cast your first pair of Skeletal Mages and watch everything explode. Devour the bodies, collect the Health Globes this creates, and you can easily cast a second maximum essence pair of Skeletal Mages, thus maxing out your Bones of Rathma 6 piece set bonus. From here it is just up to how fast you can bounce from pack to pack recasting Mages to keep 4 out at a time.
You don't HAVE to have 4 maximum Essence Skeletal Mages out at once, but with this much Essence generation you easily can while clearing rifts. If you are in a long fight vs. a Rift Guardian you'll have to settle for less powerful Mages in order to keep 4 going to maintain your set bonus. The only other advice I have is to use Blood Rush to move during combat when possible as it will not disrupt your Endless Walk damage stacks.
That is it, this is likely how Bones of Rathma is going to function into the next Season. Leave your questions and comments below!
UPDATE: Post-hotfix (lol Blizz faked me out) I've actually gotten to play with this build and I am stomping all over T13 with it despite my weapon missing 200 max dmg, and my rings / amu all being off by at least 1 enchant. Not only that my shitty Julian's Love ring is only a 2 second extension (instead of 4) and I still don't have any trouble getting 6-8 maximum Essence Mages out at a time as long as I keep the pain train rolling along between packs fast enough.
UPDATE 2: Uh... So the hotfix has been pushed back twice now and I'm still stomping all over T13. This build is going to be ridiculous on Monday when the hotfix finally, really, goes live FOR REAL THIS TIME.
UPDATE 3: Oh hey the hotfix really actually went live finally on 10 July 2017. I just finished GR80 despite my gear being pretty lackluster in terms of enchants and rolls on enchants even when I have the right ones. GR80 itself was close, but I also got really bad maps and made some play errors.
UPDATE 4: I've changed a few rune choices around. The range on Devouring Aura was too small during tough fights vs. large numbers of monsters, so while I think it is fine for speed farming, you will want to use Cannibalize in higher GRs for the massive additional range it provides. While you're doing that you can also change Command Skellies to Freezing Grasp since Devour is now healing you alongside all those globes it is generating. Due to survival being more important than speed I also recommend Potency in Blood Rush rather than Metabolism if you're pushing high GRs.
I'm messing around with this build and so far it works well, havent tried higher rifts though only up to 65 so far
Some do simulacrum to double both reilena's bonus and singularity's.
Things are going pretty good despite the hotfix not even being live yet. When it is this build will be nucking futs.
I'm doing T13 safely (and very fast) and the hotfix still isn't live yet. The thing with this 4pc set bonus (and all of them on Necro) is it requires a "build-up" to get your damage reduction going. You're extremely vulnerable to dying when first entering a new rift because your 4pc bonus isn't online yet and your belt defense bonus relies on actually landing curses before you get one-shot.
I don't think Necro is a great fit for hardcore because of this. Other classes / sets are a lot harder to kill right out the gate. However, once you get rolling you're pretty tough to kill.
As for using Bone Armor instead of Blood Rush, that is certainly an option. The 30% damage reduction is always great regardless of your Necro build. I don't find that I need it in T13 though, and a lot of my gear is still not as good as it could be. Cannibalize is fine if you are taking enough damage to justify it, but the health globes I generate have been enough to keep me rolling so far.
Giving up Blood Rush with Metabolism makes positioning and keeping your Traveler's Pledge bonus going a lot harder, and slows you down in some rifts where you can pass walls and stairs by just teleporting. If speed is your goal, imo stick with BR & M. If you just want to survive better without giving up BR, then take Potency for the double armor buff.
Tomorrow, though, you only need 4 skeletons to max your bonus unless Blizzard fucks up and pushes the hotfix back a THIRD TIME :[ At that point I'm still in favor of the ring, but it is perhaps no longer mandatory. The issue is that you spend your entire Essence bar just to build 1 Singularity Mage at that point, which will severely slow your build-up at the start of rifts and between big fights. I think if you stick to Singularity the ring is still mandatory, but if you try other (less powerful) runes you could perhaps get away with not using the Julian's Love ring because you could cast all 4 Mages before your Essence drained completely.
Update: I just cleared GR80 with this build. My gear is still very lacking despite my efforts to improve it I've made so many scythes... Anyways I think I might change Blood Rush to Potency because shit can seriously fuck you up in GR80+ You won't have the freedom to double teleport around so much without getting one shot by something.
For people asking about stat priority: whatever raises your sheet damage the most, but sometimes things that don't raise your sheet damage at all. This is going to vary from person to person, but generally the more you stack any one thing the more diminishing returns bite you. For example if you already have 60% critical hit chance, another 5% may not make as big a difference as +10% dmg vs. Elites (assuming you had 0%) or potentially other stats that don't always show up on your sheet dps.
Now, that being said, I farmed all my gems up using this build. I think Bane of the Trapped was around 60~ when I inherited it, but my Enforcer and Esoteric were rank 0.
I'm changing from Devouring Aura to Cannibalize for a few reasons, #1 being that the Devouring Aura is too small. The 10% gain in Essence per corpse is useful, but not when I'm in danger of being 1-shot while trying to get in range of corpses. Cannibalize is the only other real option and works out to help keep you capped off. I'm going to play around with Freeze skeletons and see if they can improve my clears.
I just crushed a 90 rift rather effortlessly with a little over 3 minutes left, I swapped rush with simacrilum for this insane burst potential and watched in awe as the rift guardian melted in 5 seconds. This set outclasses Trag'oul pet build by far now. Not even optimal ancients and augments or high level gems just my 80 GR stuff, pretty insane.
Forgive me if this is a super n00b question, but why reapers wraps? Wouldn't you want to run Nemisis Bracers for rare spawn or even Ancient Parthan Bracers for the DR? Also I LOVE the damage on this build especially after the new patch but I still feel super squishy like a stray arrow clips me and I become a skyrim town guard. Is there anyway w/o sacrificing BR to increase the tankiness of the build?
Just saw what reaper wraps acttually did and I totally agree now, but I still feel like when even the smallest enemy comes over and pokes me that i explode. I get dodging and git gud m8 but if i get jumped and then insta gibbed it doesn't matter how much damage I do because I'm dead. In a build that requires you to tunnel a lil to pull out decent DPS there is no room for recovery. I love this build so much but i feel useless past 75 right now. Any white mob so much as sneezes and I crumple under the force.
If this isn't enough I suppose make sure you're always running around instead of standing still to get the Endless Walk dmg redux bonus up as high as you can get it. I still get one-shot by certain whites in GR80, but usually just the charging beasts and others with long windups that I should be avoiding getting hit by anyway. You mostly get owned by that sort of attack because Esoteric Alteration is only protecting you from elemental damage sources (ie: most elite affixes).
I already explained that stat priority is somewhat fluid - read the descriptions. Just try to make your sheet damage bigger, unless you can take something you don't already have like +10% dmg vs. Elites, which does matter but won't show up in your sheet DPS.
Gizzard gem and "Bone Armor - They Flesh Sustained" is so much better than Esoteric. I'm using that with "Frailty - Scent of blood" currently but i guess it helps alot with essence regen to have Devour so i will try that. Blood Rush is not needed though. I really think you guys should try Gizzard + Bone Storm as mentioned above. At 10 stacks it currently gives me 240k healing per second.
thnx
Unfortunately for some gods forsaken reason you can't roll essence on skullshield so its 310 max and mages only use 270 of that for the damage bonus because they still cost 40 to use. Though with the hot fix if you wanna play at boss/elite melting with simulacrum (reservoir) you get another 310 for 580 times 3% for a 1740% increase and the fun doesn't stop there, because with julian's love and simulacrum at full essence you can can pop out 4 of these bad larrys with 1 cast enabling rathma 6p bonus(hotfix), throw in krysbin/bott/command skele/endless walk for stupid damage you could even save it for after a wipe to get back into play.
Would run julians on hand and kysbins in the cube for 1) its easier to roll 4 seconds when it can only get between 2-4 compared to 100 on a range of 75-100 and 2) julians always rolls crit damage.
simulacrum - doubles essence
land of dead - for globes
and see the outstanding damage.