[3.27] Dark Pact of Trarthus Life Stack Occultist

The Apostolate looks like best body armour because it grants a lot of life without life modifiers. It makes possible to take all life masteries to have maximum profit from them.

Dissolution of the Flesh makes the build possible. Instead of taking damage to our current life it reserves maximum life. With cap block and tonns of maximum life character tank most hits from uber like Maven's cascade of pain or Sirus' "Die" beams.

This shield makes the damage. The more life and energy shield on it - the better.

This amulet is cheap and grants a lot of life in exchange of gems. And this build can use this amulet because we can leave empty sockets and don't suffer from it. Annoited with chaos penetration (1 prismatic, 2 opalescent).

This jewel with this foulbourn affix in lower left corner grants +22% increased maximum life when combined with 3 fire resist tatoos.

Not best, but solid option for weapon. In my build it grants around 1.1k life on 95 level.

The Adorned is great jewel for stacking builds like this one. Need some corrupted jewels with increased life and crit multiplyer.

We need grafts with increase maximum life and one of it should be with Tender Embrace which grants endurance charges.

High energy shield base with life, ES, resistances, move speed on boots and dexterity. As implicits we seek for unnerve on gloves, avoidance for elemental ailments and shock on boots (for Stormshroud setup).

Stygian Vise with life, es, resistances and jewel with life, dexterity and shock avoidance.

Ring as other items must have life, energy shield, dexterity and resistances. Other good affixes are cast speed, crit multyplier and curse with Despair on hit.

Main skill deal chaos damage with hits and with Rapthpith Globe and Assasin's Mark we have 100% crit chance, so we add increased crit and power charge on crit to increase crit multyplier.
The main hit from this gem is when we achieve 7 stacks of ruin, so we need to cast it as often as possible. That's why I took much dexterity - for Vaal Haste with Eternal Blessing. The second part of increasing cast speed is Spell Echo which is effective doubles cast speed. And we need maximum quality of Dark Pact for chance to gain 2 stacks of ruin per cast.
Intensify grants area of effect and more damage for effect which grants a lot of damage.
Last socket in six link I put Void Manipulation which grants a lot of damage. As possible variant can look for Enhance (haven't tested it) that will greatly increase frequency of ruin stacks gaining, but it needs some invests in life regen.
Other gems are just for more comfort: flame dash for dashing, tempest shield for capping spell block (reserve life) and linked with void manipulation to avoid elemental reflect on maps.

I chose Aul for stun and slow immune. Other possible is Nameless for extra ring slot instead of flasks.