LoD Mammoth Hydra Wizard Skills and Runes

Active Skills
Spectral Blade Barrier Blades Black Hole Spellsteal 1 Teleport Safe Passage 2 Blizzard Unrelenting Storm 3 Hydra Mammoth Hydra 4 Storm Armor Shocking Aspect
Passive Skills
Galvanizing Ward Elemental Exposure Arcane Dynamo Audacity

You will start runs with an activation of Storm Armor, which is to be kept up throughout the rift. Once you come across a decent pack of monsters, prepare the pull with a Black Hole to clump them up, then close the distance — either by walking or engaging with Teleport — in order to trigger the bonuses of the Audacity passive. Then, pre-cast a Blizzard to trigger the bonuses of Winter Flurry, and buff up your Fragment of Destiny effect and Arcane Dynamo passive with Spectral Blade prior to summoning Hydras. Re-buff and re-cast Hydras manually as they expire. In the ideal case scenario, you will have the Black Hole cooldown up 1 second into you Cold CoE rotation, so you can affect the pull with the Spellsteal debuff prior to your burst period during the Fire Convention of Elements cycle. Your Blizzards should be cast at 8-second intervals, lining up with the start of the Lightning and Cold CoE cycles. If you get an Oculus Ring proc (the ring is worn by your follower), quickly Teleport to it for the potent damage buff.

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. Note that Hydras are an extremely attack speed breakpoint-dependent skill, and refer to the Gear page for additional details on the advised breakpoint. Mechanically speaking, the Mammoth Hydras target the nearest enemy to their spawn point and cast their "river of flame" effect, extending at a 50 yard range in 10 yard increments over a 1.8-second period, lasting for 3 seconds per line. The linear AoE effect has a tick rate of 0.3 seconds and deals its damage instantly as it reaches the monster. In practice, this means that placing the Mammoth Hydras point blank to the enemy is optimal for your damage potential, and every meaningful distance you create between the Hydra and the target (5 yards+) will cost you substantial damage.

You will be taking Blizzard by necessity due to the revised powers of Winter Flurry — now transformed into a Hydra-specific source that amplifies the summons' damage against enemies within the Blizzard radius. To extend this benefit and minimize these supplementary casts, you will be taking the longer lasting Unrelenting Storm rune. In order to cover the entire duration of a Convention of Elements cycle (16 seconds), you will only need to cast it twice. Another viable rune for the slot is Apocalypse, which trades duration for a wider area of effect — also quite useful in the right scenario. Note that alternating to Apocalypse all but invalidates Elemental Exposure as a passive choice, but other options exist, as noted below.

With the revised powers of Fragment of Destiny — now improving the damage of Hydras with a stacking mechanic depending on Spectral Blade, you will have to include this primary attack by necessity. The rune of choice is Barrier Blades, which supplements the shield-based protection of the build and synergizes nicely with Ashnagarr's Blood Bracer. Additionally, Spectral Blade is also your main means of stacking Bane of the Stricken on the Rift Guardian.

Black Hole will be taken into the build as means of crowd controlling the enemy and building up large pulls. You should take the rune Spellsteal, as it offers a good balance between additively increasing damage against, while also decreasing damage from, enemies that are afflicted by its radius.

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 massive damage reduction properties of Halo of Karini (see this build's gear page for more information). You will be taking the rune Shocking Aspect for the superior uptime of the procs for the Karini buff. Alternatively, you can consider Scramble for the additional movement speed.

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

Arcane Dynamo offers a whopping 60% multiplicative increase of your next spender with fully stacked Flashes of Insight, enforcing a rotation of Spectral Blade stacking (both this passive as well as the Fragment of Destiny effect) prior to putting a Hydra down. Note that other non-Signature skills in the build, such as Blizzard or Black Hole, can consume the buff — so you need to be careful with the sequencing of your skills.

Added with similar reasoning to Barrier Blades (mainly Squirt's Necklace buff maintenance), Galvanizing Ward introduces a solid damage buffer that benefits from the doubled effectiveness via Ashnagarr's Blood Bracer. Note that in the order of shielding buffs, the Barrier Blades layer will be consumed first. It is quite important to refuel that temporary, smaller shield through Spectral Blade attacks in order to give time for your bigger damage buffer, Galvanizing Ward, time to rebuild.

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 slash away with Spectral Blade.

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, cold with Blizzard and arcane with Barrier Blades. The final bump will come from the damage type of your weapon, Serpent's Sparker — a lucky roll (or reroll) of the base damage from another type (i.e. physical or arcane) into lightning will bring the last piece of the damage buff. Note that this is also the least valuable passive in the build, so you can adjust according to your preferences; if you value extra mobility, Illusionist is an excellent addition for the slot. If you require additional safety, swap out for a defensive staple like Blur.