LoD Mammoth Hydra Wizard Skills and Runes

Active Skills
Arcane Torrent Static Discharge Hydra Mammoth Hydra 1 Black Hole Spellsteal 2 Teleport Safe Passage 3 Storm Armor Power of the Storm 4 Magic Weapon Deflection
Passive Skills
Galvanizing Ward Elemental Exposure Illusionist Audacity

You will start runs with an activation of Magic Weapon and Storm Armor, both of which are to be kept up throughout the rift. Once you come across a decent pack of monsters, close the distance — either by walking or engaging with Teleport — in order to trigger the bonuses of the Audacity passive, summon two Hydras and start channeling Arcane Torrent. Your next, Etched Sigil-induced Hydra summons and Black Hole casts should follow promptly, and you will rinse and repeat that process from fight to fight.

Your primary damage dealing skill and namesake of the build is, of course, Hydra. In the LoD version of the build you are not constrained by the Typhon set limitations of multi-headed Hydras, and you are free to take the highest damage dealing rune of the bunch — the single-headed Mammoth Hydra.

As previously noted however, you will be summoning the Hydras not through manual casting, but through channeling and the powers of the Etched Sigil. The preferred skill to channel is the Wizard staple Arcane Torrent. You can either take it with the Lightning rune Static Discharge to maximize the benefits of the damage buff from Elemental Exposure, or with the Flame Ward rune for additional protection — remember that this skill is not taken for its damage, but as means of summoning and damage amplification from Deathwish.

Black Hole is an excellent utility inclusion for several reasons. First, it brings a monster grouping skill to the setup, which is always welcome before you start your channeling barrage; second, it packs a utility combo of reducing enemy damage and increasing your own via the rune Spellsteal; and third, it acts as a proc for the Arcane portion of the Elemental Exposure buff. Since this skill is a spender, it will also be activated for free from the powers of Etched Sigil while channeling.

Magic Weapon offers an attractive, long-lasting damage buff by default, which branches our even more nicely into defense via the rune Deflection — highly desirable in order to safeguard your Squirt's Necklace damage buff. Note that this protective effect is doubled via the worn Ashnagarr's Blood Bracer, if you choose to wear it.

Sometimes immediate repositioning will be required — evading a bad affix, engaging a larger pack of enemies to maximize the Mammoth Hydra AoE, or simply to gain a temporary Toughness buff in a rough fight. Teleport will cover you for all these purposes, along with the damage reduction of the Safe Passage rune.

Rounding skills out, you will be adding Storm Armor to the build. With a fire-and-forget duration of 10 minutes and a negligible damage proc, it can be easily overlooked if not for the potent flat resource cost reduction of the Power of the Storm rune and the massive damage reduction properties of Halo of Karini (see this build's gear page for more information).

This concludes the overview of the Active Skills, now let us look through the Passives.

Illusionist is one of the strongest utility picks in the Wizard's arsenal, offering an immediate reset to the vital Teleport upon sustaining a hit that takes 15% of your max life (which is basically every hit in a GR progression attempt). On top of that, the passive grants a 30% movement speed increase upon the use of Teleport, making for very consistent speed buff throughout the Rift.

Added with similar reasoning to Magic Weapon Deflection (mainly Squirt's Necklace buff maintenance), Galvanizing Ward introduces a solid damage buffer that benefits from the doubled effectiveness via Ashnagarr's Blood Bracer.

Audacity brings a sizable 30% multiplicative damage increase against enemies within 15 yards — a near-melee range prerequisite that you fulfill naturally through the playstyle of the build, as enemies close in on you while you channel.

Elemental Exposure rounds out your passive selection with a final, decent damage increase. Notice that the passive bumps damage in 5% increments per element used; you fulfill the fire with Mammoth Hydra, lightning with Static Discharge and arcane with Spellsteal. The final bump will come from the damage type of your weapon, Deathwish — a lucky roll (or reroll) of the base damage from another type (i.e. physical or arcane) into cold will bring the last piece of the damage buff.