Energy Armor (known as Energy Shield prior to July 2011) is a Conjuration Wizard skill unlocked at Level 28, which uses Arcane Power to absorb incoming damage.
This is an Armor spell. Only one Armor spell can be active at a time.
Drawing from long forgotten texts, this magical shield of energy absorbs harmful attacks through energy resonance, draining Arcane Power.
Refer to the Energy Armor rune effects article for thorough descriptions of all five rune effects in this skill, including screenshots, videos, strategy tips, and other related information.
<skill subcat="Armor spell" class="Wizard">Energy Armor</skill>
<skill class="Wizard" rune="Absorption">Energy Armor</skill>
<skill class="Wizard" rune="Pinpoint Barrier">Energy Armor</skill>
<skill class="Wizard" rune="Energy Tap">Energy Armor</skill>
<skill class="Wizard" rune="Force Armor">Energy Armor</skill>
<skill class="Wizard" rune="Prismatic Armor">Energy Armor</skill>
The skill with lots of heritage is back in Diablo III. It's a shield that absorbs all damage taken, converting the damage to Arcane Power loss, draining 2 points of AP for every point of damage absorbed.
This skill is likely to be used by many Wizards, especially if they are going melee-style with Diamond Skin and Magic Weapon, or playing hardcore.
The following Wizard passives provide a benefit to Energy Armor, runed or not:
<skill class="Wizard">Galvanizing Ward</skill>
Energy Armor first appeared in the BlizzCon 2009 demo (then named Energy Shield), located at Tier III in the Arcane Skill Tree and already one of the D3 Team's favorites. Flux didn't have much to say about it, unfortunately. The full quote:
Not a skill I even considered using, in the easy Blizzcon demo.
Skill trees were removed shortly thereafter. At BlizzCon 2010, Energy Shield was a Tier 5 skill, making it too high-level for players to select.
Skill tiers were removed for the July 2011 Press Event, allowing skills to unlock steadily from levels 1 to 30. Consequently, all skill levels were adjusted and Energy Shield became a level 22 skill and was renamed Energy Armor.
The Diablo III Beta started in September 2011, and while it ran, all of the skills continued to undergo extensive iteration. Skill changes varied from changing the levels the skills are unlocked, to changes in resource cost, damage, and even function. A few skills were removed altogether, and a few new ones were added. Also, the entire skill system received an overhaul with the Beta Patch 13 update in February 2012, with physical runes replaced by rune effects that automatically unlock at various levels for the different skills.
Energy Armor remained at level 22 when the beta started. With the Patch 13 changes, it was classified as a Conjuration skill and bumped up to level 28.
Energy Armor is similar to, and might have replaced, Temporal Armor. That skill was seen in the BlizzCon 2008 demo, and had a slightly different mechanic: protecting the caster from 100% damage once every 6 seconds. Something that could be either very good, if it fended off a strong attack, or quite useless, if it fended off a weak one.
See Energy Shield for the original version of this skill.
Energy Armor originates from the grossly overpowered Mana Shield from the original Diablo game, where every point of damage translated into mana lost instead of life. The spell had unlimited duration, as long as the character didn't die or travel to another level.
In Diablo II, the Sorceress got a nerfed version of the same spell but with the name Energy Shield. The spell has a time limit (needed, since no levels were limited by loading) and only absorbed a fraction of the damage.
Energy Armor can be seen in action on video here:
You can find pictures in the Diablo III screenshot and picture gallery: