[3.0] Doubly Cursed Cosmic Caster - Screw the Meta guide to LL Frostbolt (100k+ tooltip DPS)

The Doubly Cursed Cosmic Caster is a Frostbolt / Vortex build that focuses on ramping up cold damage, crowd control (chill, freeze, Temporal Chains), and leech in order to provide a stout build that is fast and reliable. Although you'd be forgiven for thinking "GMP" at first glance, this build doesn't use GMP or LMP. It goes for high sustained DPS, and doesn't utilize skills that scale back damage.

This build plays mid-range, although at times calls for long-range and point-blank. It can handle both thanks to its leech, solid ES, and ability to concentrate damage using Vortex. It was built specifically with the Harbinger League in mind, as this league is all about huge DPS against packs. As such, the Cosmic Caster does exceptionally well against groups, although it's flexible enough to handle bosses and single-targets too.

Cosmic Caster is fast. It draws on Whirling Blades, Vaal Haste, Onslaught, Phase Run, and Quicksilver potions to help propel you through maps so quickly that you're often racing ahead of your Frostbolts. Its enhanced mobility allows for easy positioning and map advantage, which helps make it an easy to play, fun to master build that supports a variety of play styles.

Pros
Fast clear speed
Great against packs (perfect for Harbinger league)
Flexible with map mods, very few deal breakers
Fairly cheap
Levels well
Looks baller as hell, especially with MTX
No one else in your party will know WTF you're doing

Cons
Can be a little weak against single targets/bosses
Requires 6L Shavs
Not HC friendly (would need to respec more life)
Say "buh-bye" to your FPS when you party
Everyone else in your party will want to know WTF you're doing

Levels 1-30

Levels 1-60

Levels 1-90

Full Tree

OLD - My Current Tree
Up-to-date My Current Tree

Kill Oak
Kill Alira
Save Kraityn

6-link:
Frostbolt
Spell Echo
Faster Casting
Life Leech
Onslaught
Ice Bite



4-link:
Vortex
Faster Casting
Life Leech
Efficacy


4-link:
Cast When Damage Taken (level 3)
Phase Run (level 5)
Summon Lightning Golem (level 5)
Summon Ice Golem (level 5)


3-link:
Cast When Damage Taken (level 7)
Discharge (level 10)
Ice Nova (level 11)


3-link:
Whirling Blades
Faster Attacks
Fortify


3-link:
Blasphemy
Temporal Chains
Warlord's Mark


Single Gems (fill empty sockets):
Vaal Haste

There are only a couple of required items for this build; fortunately they are pretty cheap. However, there are some strongly recommended items as well, including a 6L Shavronne's Wrappings. Get these as you can, currency allowing.

Helm:

Vertex is highly recommended because it is inexpensive, offers high ES, and offers +1 to gems. Make sure to socket your Vortex 4L in this.

Heretic's Veil is an alternative.

I have experimented with dropping Blasphemy from my gem setup and using it instead. Unfortunately I've not yet gotten to the point that I'm comfortable with 3 curses or 2 curses + an aura while still leaving enough mana.

Chest:

Shavronne's Wrappings is highly recommended because it offers us a (relatively) high ES chest with chaos protection. Huge quality of life item. You could run this without it, but I wouldn't want to. Worth the EX. If you don't run this, you'll need a different tree (more life nodes) and a lot of chaos resistance on your gear.

Gloves:

There are a couple of options for gloves. By end game, with the above mentioned gem setup, you'll want gloves that offer high ES and resistances. You'll also likely need to get some dexterity from your gloves, as this build lacks it otherwise.

Another option for leveling:

These were incredibly useful for leveling, and I almost didn't swap them out. Having the free Temporal Chains curse on hit allowed me to save mana and gem slots. Only toward upper-tier maps did I decide to swap this out in favor of running Blasphemy + Temporal Chains because I wanted a higher level Temporal Chains and the extra ES and resists from GG gloves.

Boots:

A good set of rare boots is your best bet here. Aim for high ES, 30% movement speed, and resists.

An interesting alternative:

I ran these for quite awhile, and sometimes I'm still tempted to throw them on. They offer a big dexterity boost, which our build needs. They offer 30% movement speed. Coolest of all, you get phasing from your kills, which means you're basically always phasing. Oh yeah, and the Celestial Footprints look awesome. This is a cheap unique, and if you can't find solid GG rare boots, I'd recommend these. You'll be lacking some ES and resists, but they're still a good choice.

Weapon:

A good rare spell dagger is a must, because we want to run Whirling Blades. As with all spell blades, look for spell damage, crit, and cast speed.

Shield:

A good rare shield helps round out our build significantly. Look for high ES, resists, and then spell damage and dexterity if you still need it.

Belt:

Use a good rare belt that rounds out your Dexterity and Strength, as well as your resists. This slot is your chance to make those things work so you are capped and have all the necessary stats.

If you can find one that works for you, I'd specifically recommend a crystal belt:

I've not found the right one yet (tri-resist + ES), but if you can get one that has the ES, stats, and resists you need, go for it.

Amulet:

Having a +1 curses amulet is important for endgame. They tend to be pricey, so buy what you can afford. If you can afford one with spell damage, ES, resists, etc., that's the best. Otherwise, just do the best you can.

While leveling, if you can't afford one of these, then you can spec the +1 on the tree (just respec later), or you can use one of these:

That's what I did, which I think is the easiest solution.

Rings:

These are mandatory. Fortunately, they're also cheap. They are amazing for our build, giving us 2 extra Frostbolts, as well as increasing our damage and giving us resist to cold. Get them as soon as possible.

Potions:

Use whatever potions you like, although I've found Atziri's Promise and Rumi's Concoction to be really useful. You'll need a mana pot most likely, though your leech will often negate the need for it. You'll rarely need the life pot, but when you do...

Jewels:

These are mandatory for our build. These things are what allow us to skip GMP and LMP. They give us 4 extra Frostbolts, speed them up, and make them hit harder. I'd run more if I could.