Build Guide
Build Notes:
This is a CASUAL play build, meant to be fun and fairly potent, but I'm not TRYING to get it to push GR100+ although if it manages to do that I'd be very happy. I'm gradually pushing it to see how far I can take it.
This build meshes a Trag'Oul's 6pc bonus with the fun of a pet build, and does amazingly well. It is a modification of the build found in this video where the biggest problem I had with it was the fact that it can starve on Essence really easy when you trigger 'Command Skeletons' too often or when you're having to cast 'Skeletal Mage' a bunch if you don't have Circle of Nailuj yet - such as in boss fights or transitions where you haven't had corpses in a while and your mages die off.
The use of Frailty/Corroded fang instead of Ice Golem/Scythe of the Cycle is purely because I don't HAVE one yet and so this was the cleanest way to get a constant and smooth multiplicative damage boost, plus the damage reduction from the belt, PLUS the essence recovery from cursed enemies option if you still feel you are starving (so far I haven't needed to use 'Harvest Essence' rune yet).
When this build was incomplete (just Trag'Oul's 6pc and Jesset set) I was able to clear pretty easily up to T7 or 8, and once I got to the full build detailed in this page Torment X became a walk in the park, and I'm still seeing how far I can push it. So far I have never been at risk of failing a GR (currently pushing past GR50) - the biggest risk time at higher levels is when you just start and your bone armor isn't up to max stacks.
Damage Estimation for Skeletal Mage (ideal conditions, with all bonuses applied)
All of the following should be multiplicative/stacking (my apologies if I don't write/notate it correctly here):
Base weapon * 400 (Skeletal Mage) + 3300 (Trag'Oul's) + 200 (CoE) + 200 (Corroded Fang) + 50 (Tasker) + 300 (Krysbin) + 400 (Jesseth) + 20 (Bane of Powerful) + 25 (Varies on level of Bane of Trapped) + 25 (Varies on level of Enforcer) + 15 (Frailty, plus however you calculate in the 'death at 15% thing).
On T8 lazy running around, my skeletons regularly do 20million'ish in damage and my mages top a few billion on damage per hit. On GR 52 (current max, 5-6 min finish) bosses melt in about 4-6 seconds of focused damage.
Ability/Cast priority:
The secondary ability general priorities (1-4 keys) are pretty much in the same order as I put it on the skill list above:
'Devour' -> 'Skeletal Mage' -> 'Frailty' -> 'Command Skeletons'
Note: You're not going to want to toss out a 'Command Skeletons' unless you have over half Essence, it takes a lot of juice so it's a definite risk versus reward type ability in low population areas, even with all the Essence recovery options built into this build.
Your 'Bone Armor' ability is free but on a cooldown, but since it's on your LMB that's pretty much auto-cast as you move around. Blood Rush is also free thanks to the Trag'Oul's 2pc set bonus, and has the added perk of leaving a corpse every time you use it, so USE IT OFTEN and feed yourself Essence and the chance to spawn health globes at every opportunity.
Play style:
You're going to start off in a rift moving forward and then halt as soon as you see any movement. Let your Skeleton Warriors engage and keep the enemy busy while you cast your mages (4 casts worth). Dive in briefly to get a 'Bone Armor' cast off and start building your toughness up; then toss out a curse, toss out a 'Command Skeletons', and let the gibs fly. As you get farther into the instance you should be able to keep a steady flow of mages rolling. In situations with LOTS of mobs, you can easily keep 8-10 Mages up even without the Nailuj item.
NOTES: I just ripped through GR52 - first run, still pushing up to see how high this kit goes - with a 4:30 time. No deaths, no resource issues, full clear of all trash along the way. The hardest part? Can't open doors, you have to command your skeletons to do it for you.
Usage notes:
I finally managed to pick up a few items to hopefully boost this set even further, here's my thoughts on their actual use.
Scythe of the Cycle
400% damage boost to Secondary skills while bone armor active,
shortens bone armor by 4 seconds
On the surface, this seems pretty nice.. BUT - 'Secondary skills' is only 'Bone Spear', 'Skeletal Mage', and 'Death Nova'. On top of that is that your bone armor drops by 4 seconds for EVERY cast of Skeletal Mage. With a 10 second cooldown, and needing to cast Skeletal Mage pretty frequently, you're going to be riding the bleeding edge of being VERY squishy again very often - not fun.
It also means that skeletal mages are the only thing getting any sort of damage boost - which I suppose isn't exactly bad since they are your heavy hitters, but there are limiters: first is the 400% boost is only for the Mages (which is further affected by the CoE boost limitation since it's physical), next is that it depends on your bone armor being active (did you die? did your casting habits consume your buff? Yeah.. all bad.). Compare that to the Corroded Fang which says that 'you deal 200% extra damage to cursed enemies' - this is bonus damage from ALL sources against the enemy, regardless of anything else, as long as they're cursed. It's not a big risk vs reward boost like the Scythe is, but the smooth damage output wins big in my book. Plus rather than being additive damage like the scythe is to your skeletal mages base level, it's multiplicative to the entire value of damage that you do to the enemy as a whole when you land a hit.
Wisdom of Kalan
Increase max stacks of Bone Armor by 5
his is kinda self explanatory, you go from 30% damage reduction to 45%. Granted, you lose a passive from the Hellfire Amulet but that was a pretty big random roll to start with (I got super lucky with Dark Reaping), and the Eternal Torment passive wasn't too big a deal anyway, just helpful in reducing cost.
Cord of the Sherma
Chance on hit to blind/slow enemies
Part of what makes this build potent is the Krysbin, which does 100% extra damage to slowed enemies, or 300% for any other negative status effect. So the more chances you get to stun/freeze/blind/fear/etc is going to pay off big for you. It's a hard toss-up for me on this one vs Dayntee's Binding because Damage Reduction = survivability, plus while the proc rate per hit is pretty good this item seems to have an internal cooldown ('field lasts for 4'ish seconds, can't happen more frequently than once every 10 seconds' kind of thing). This feels a bit like the Ice Golem's cooldown, and cooldowns are bad. So while I do like this item for it's potential (and for free, no less - compared to Command Skeleton).
Decrepify (Dizzying Curse)
10% chance to stun for 2 seconds on hit
This goes hand in hand with Dayntee's Binding, really. You want ways to give status problems to targets so that you can get nice damage boosts, the problem with this one is that it's single target per hit vs the bubble/field of Dayntee's. Worth a try though.