Level 99 CI Raise Spectre Necromancer^3.24

Notes

Spectres: Use carnage cheiftans from act 2 until you get Primalcrush claws (ask in /global 6666 for primal crushclaws or get them from rare blue harvest)
Primal crushclaws is by far the best spectre for this build.

Minion skill GEM LEVEL is much more important than QUALITY
21/0 >>>> 20/20    Spectres/golems/skeletons/zombies/phantasm/AG

You want one ghastly eye jewel with taunt on hit and if possible Blind on hit as well (Blind and taunt can be on seperate ghastly eye jewels for example the ones in the belt)

For Low/Medium/High Budget:
Stygian Vise =/= Darkness Enthroned, depends on what's easier to sort chaos resistances & dexterity requirements. Phase Run & Dash can be lower lvls to help mitigate the attribute starvation.

LOW BUDGET NOTE

Spectres: 
2 primal crushclaws (Blue harvest)
1 Carnage Cheiftan (Act 2 The old fields)
1 arena master

You dont need to have unending hunger but it helps with clear speed. (skip it if it costs a lot)

Use +1 to socketed gems on the ag unset if +2 is to expensive.

Use corrupted bones of ullr with +2 minion gems if they are cheap.

You can use determination + hatred + skitter bots if you have mana reservation efficiency implicit on the helmet from eater of worlds.
You add this by using lowest tier of eldritch ichor.
Another option instead is to buy a cheap corrupted amulet with charisma anointed.

For low budget AG body armour use either Zahndethus or gruthkul or doppleganger, Gruthkul and dopple are better than Zahndethus but more expensive.

You can use skeletons for 2.2m more damage instead of minion damage support in 6L body with zombies.
The reason you replace minion damage instead of anything else is to avoid gem color swap and your skeletons and zombies do not loose 25% life. 
Using skeletons will also trigger the minion mastery to recover 5% minion life on minion death a lot more.

Convocate on top of tanky rares / bosses to focus dmg. (So dont use convocate on move)

For Ultimatum mechanic use skeletons.

If you manage to get the resistances/attributes you need without having any on body armour, get a 6L vis mortis or 6L replica covenant. if its within your budget for more dmg and ehp.
or non-corrupted rare 6L with two eldritch implicits (hatred+non-curse aura)

If you use hungry loop in low budget use ruthless instead of elemental army with zombies, move culling to golems and get min damage for spectre+phantasm.