Level 86 Summon Raging Spirit of Enormity Necromancer^3.25

Notes

Pragmatism 3 offcolors: 2 blue benchcraft then 3 sockets - 2 sockets "vorici trick" to make 3 sockets blue
Can go with any 6L like tabula but mana costs will be enormous. You'll have to use unleash

4th ascendancy is either plaguebringer or mistres of sacrifice mostly for guard skill duration

This version is no way tanky, I only used it to get eater and exarch watchstones and then respec
Main defence mechanic is 6 portals and cast on death portal to save time

Shenanigans: When you already have 6 spirits active you gotta stop casting them as old skulls will be replaced by new without exploding so you will have 0 dps if you do so
And you'll likely start casting when there's 2-3 of them still active
That's why your true dps is like 2/3 of max (like if 4 out of 6 skulls are activated )
More shenanigans: srs cannot taunt so I use zombies to distract enemies more or less. They die frequently
Even more shenanigans: you'll have to precast 2-3 srs before stepping ino unrevealed map area

Gear

You don't really need replica dragonfang or ashes, tavukai is 3c at most at any day of the league. It also provides unconditional degen to srs minions so they degen while flying to an enemy and require less hits to explode.
Tho Ashes have batter paper dps Tavukai imo have better damage application and available at league start.
Rainbowstride is cheap and also available and offers nice stats overall
Breathstealer allows annointing another passive 
Deceiver belt is just a cheap stub for resists
Wand is self crafted just use essence of fear once or twice and then benchcraft trigger
Buy any bone helmet, obtain 2x any minion gems of +20% quality and vendor that items to get +1 minion helmet. Then aug, regal and benchcraft life.
Bone rings can be bought cheaply as this combination of stats is worth nothing. If it becomes too costly just use essence of fear once on any bone so you'll have only minon life affix but that should be enough

Flasks may vary and better be enchanted for auto use

Total budget is around 30-50c on day 2 on normal league start (found it impossible to start with on resettlers event due to low number of players)

Tree

Despite having necro aegis we still benefit from shield block nodes
Resistance nodes are here as a stub. Build have many uniques and not that many rares so gotta have 75% res cap elsewhere which realistically means only on passive tree
Passives are just life, minion stats, resists, mana reservation and necro aegis, nothing fancy