[2.4] The Plumber, a Vortex Trap Saboteur. Cheap and efficient

Pros:
- Cheap (you can make to endgame with a few chaos, or even SSF) and flexible
- You don't have to worry about reflect, neither any whatsoever map mod (some could be annoying at worst)
- One of the defense layers is built-in in your attack
- Quite fast clearing speed. Some bosses actually melt.
- Non-meta: it will hardly be nerfed in the future. It may be your next league starting build.
- In the right hands it's Atziri, Izaro, Guardians/Shaper and Hardcore viable.

Cons:
- Being full evasion, you can be easily one shotted
- Even if it's very short, trap cooldown time can put you in some sketchy situations
- You may need to disperse some skill points and jewel affixes to sustain mana and stat requirements
- Leveling Vorici can be a pain in the neck
- Vortex can make bearers' balls hard to spot until it's too late

Normal: Oak or kill all
Cruel: Kill all
Merc: Kill All; (power charge if going for crit)

SAB, non crit, life based

Since Vortex damage scales a lot by itself, you don't need to go specifically for damage nodes (Snowforged and similar), neither DOT nodes. Just focus on life and take everything you need while passing by. Of course you're gonna need all the trap efficiency nodes, with a particular focus on Clever Construction, wich you will need as soon as possibile.

As I said, this build is very flexible. The one you see is the path I chose, but you can adapt it to your taste/necessities/budget. It can be made into crit, low life, CI, Hybrid Eva/ES just with a few corrections on the tree; every point needed is at hand. I didn't try it, but I'm sure that it can work even for the other two Shadow's Ascendancies, as well as Occultist and Elementalist. In those cases you might need a Sunblast.

On a side note, you might notice more than one similarity with some Ice Trap skill trees (in particular Pohx and Alive_asd ones). That's because when I had the idea of a Vortex Trap build, during Prophecy, there where none to offer me a starting point, so I looked for something similar. So, credits to you, guys, for inspiration :)

Ascendancies
Normal: Bomb Specialist
Cruel: Chain Reaction
Merciless: Blinding Assault
Uber: Born in the Shadows

Explosive Expert has always been in my wishlist, but then I realized I didn't really need even more damage but a better blind mechanic.

Vortex -> Trap -> Controlled Destruction -> Cluster Traps -> Conc Effect -> Trap and Mine Damage

This is your main (let's say only) attack skill. Throw traps on the ground and enjoy the huge AOE and overlap you get, even with Conc effect

Orb of Storms -> Faster Casting -> Power Charge on Crit

This is extremely useful to proc Elemental Overload and Elemental Equilibrium. Power Charges will boost your crit chance even on non crit version, so you will see a lot more of mobs exploding thanks to Pyre (result of ignite)

Blasphemy -> Temp Chains

Slow enemies and let them suffer more from cold degen and ignite. That's the reason I prefer this over Ele Weakness and others

Grace (Discipline for ES based builds, of course)

Lightning Warp -> Less Duration -> Faster Casting

Not just a movement skill, but my only way to succesfully complete the "keep the target at low life for 10 seconds" Vorici mission...

Stone Golem

I started with flame golem, but soon I found out I didn't need the damage boost, while life regen and taunt help a lot

Decoy Totem

Again attack and defense mechanics together. Place totem, let the mobs run to it, throw traps, collect loot. I will talk defence later.

Vaal Lightning Trap

Shocking ground, whenever you need that 50% more damage...

CWDT -> Immortal call -> Increased Duration

Useful to deal with barragers

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Other useful gems you should have with you

Artic Armour: use this instead of Temp Chains for Hexproof maps
Added Cold Damage: use this instead of Cluster Traps for single target and bosses
Elemental Focus: use this instead of Controlled Destruction for immune to status ailments maps and bosses
Trap Cooldown: very useful while leveling, until you get Chain Reaction. Then you can drop it.

The only item that can be really said to be mandatory (but just because it defines the build itself) is Pyre. And it's one of the cheapest uniques on the market, not to mention one of the easiest dropping ones. It's full cold to fire conversion will change only the initial damage, not the cold degen, leaving mobs to deal with a constant 50% less cold resistance due to EE. On top of that a highly probable (at least 20%, with 9 to 11 traps explding simoultaneusly) ignite will give you a second powerful damage over time. Want a third one? Get yourself a Consuming Dark (or two, and an Infernal Mantle, don't put a limit to your desires).

Deerstalker is very useful for leveling, giving you a 5 link very early in the game. You can drop it when you manage to get yourself a 5+ link body armour (I luckily dropped a 5 link chest piece during normal and took it with me until maps, so I didn't have to use those boots).

As I said before, Sunblast is not so useful for a Saboteur (maybe for other classes). It's not worth the space for more life and resistences.
If you feel to be ok with life and resistances, get yourself a Doedre's Damning for a second curse (maybe selfcast, or putting Curse on Hit on Orb of Storms, or instead of Grace, choose your own)

I chose dual wielding rare wands with as much spell/cold/fire damage as possibile, but you can use scepters, daggers (for crit) or weapon and shield. Eclipse Solaris is the only unique wand I would recommend, if you want to work more on blind, but it takes away some damage.

Useful alternative uniques can be Divinarius, Consuming Dark (you loose dps, but gain poison, reaching triple degen), Jaws of Agony, Doryani's Catalyst. Shavronne's Wrappings is of course mandatory for a LL version of this build.

"Basically, run!"

- Evasion: this is the real challenge. I started as hybrid Eva/ES but I switched when a friend of mine lended me a 1800 Evasion 6 linked Zodiac Leather. My survivabilty didn't change at all. Of course with more than a little help from the other layers. A jade flask is a good add-on, but stibnite is better. Grace is a bit demanding, mana wise, but manageable. I currently use a Carcass Jack, which is not cheap, I know, but nothing (except AOE) has changed much. I could afford it because I saved a lot of currency in the meantime (that's what cheap builds are made for).

- Dodge: with Evasion, Dodge is pretty much a natural choice. If you don't need a mana flask (I didn't, for a while) a quartz flask will make dodge even more efficient.

- Blind: evading attacks is good, make mobs less able to hit you is a step forward. Blinding Assault, Born in the Shadows, stibnite flask, a Blind Support gem (i linked it to Stone golem and Vaal Lightning Trap, it works) and Eclipse Solaris (if you accept a slight loss of dps), are there to make mobs' accuracy half its value. Why don't take this chance? Plus, I don't know many blind immune mobs.

- Chill and slow: Vortex chill effect in combination with Temp Chains make enemies very slow. Leapers will almost stop mid air, giving you plenty time to move or warp in a safer position.

- Taunt: of course, the best way to not get hit is to make mobs have another target. That's what Decoy Totem and Stone Golem are there for. And, a I mentiond before, a decoy is the best way to lure mobs into a trap. Thus making you a trapper by definition.

- Immortal Call: why not?

This my personal experience, so take it as it is.
I started with Fire Trap and Freezing Pulse. I switched to Firestorm + Trap as soon I could, then Vortex + Trap, started using Pyre and dropped FP. By then it was just a matter of finding the right links to put on the other gems.
You would need to get Decoy Totem from other sources (trade, drop, friends, a mule), because you can't get it from vendors.

I started using Orb of Storms when I reached Elemental Overload first and EE soon after. Those, combined with Master Sapper's frenzy charges will boost considerably your damage output.

Use Trap Cooldown Support until you get Chain Reaction (the turnig point of the build), then discard it in favour of Cluster Traps. Don't panic before the dps drop: multi vortexes overlap will take care of that. And the huge amount of dps you gain every time vortex gem levels up will make you forget it very soon.

Skill tree wise, go for Clever Construction as soon as you can, then set your goal on life nodes and Acrobatics/Phase Acro and take everything needed (other trap nodes, AOE, jewel sockets, crit/es nodes if you're planning differently from my tree) in you way. Don't hesitate to take the +30 dex/str nodes and even keep them until endgame. You will probably need them anyway.

On jewels look mainly for cold damage (much better than fire for obvious reasons), trap damage, spell damage while dual wielding (or holding a shield), all of them are prefixes and make for very cheap jewels. They are more efficient than area damage, spell damage, damage, damage over time; all suffixes. Then go for mana cost reduction, str/dex and resistances if needed. Rare jewels can be much more efficient than any unique, so you don't strictly need to have Cheap Construction, Coated Shrapnel, Hair Trigger or Unstable Payload.