Diablo III- Skills Article CXXXVIII: The Wizard, Conjuration Skills- Energy Armor

Energy Armor (25 Arcane Power): For the next 120 seconds, your maximum Arcane Power is reduced by 20 and your Armor is increased by 65%.  You can only have one Armor active at a time.

Energy Armor took the juncture that is the step from Diablo II to Diablo III in stride, and despite becoming a different animal, remains highly effective.  In Diablo and Diablo II, all classes had a Mana pool, and that Mana pool always grew with the character’s level, much like the Mana pool of the Witch Doctor class.  In those days, Energy Armor used your Mana to absorb damage alongside or instead of your Life.  The Wizard, however, has a set amount of Arcane Power that never grows- so having Energy Armor continue to act that way would never work.  Instead, this form of Energy Armor flat out reduces your total amount of Arcane Power in exchange for a massive boost in your Armor.  Initially this seems terrible- it doesn’t protect against elemental attacks at all- but remember that you’re a Wizard.  Intelligence is your primary attribute, the one you pump as high as you can- and it’s the attribute that gives you elemental resistances.  This means that Energy Armor actually shores up your one true defensive weakness, making you far more durable in all forms of combat.  It’s a rough competition between Ice Armor and Energy Armor, too, so make sure you try both before sticking with one.

Absorption (25 Arcane Power): For the next 120 seconds, your maximum Arcane Power is reduced by 20 and your Armor is increased by 65%, and whenever you are hit by a melee or ranged attack, you gain 4 Arcane Power.  You can only have one Armor active at a time.

Absorption more than makes up for the loss of a chunk of your Arcane Power pool by causing you to generate large amounts of additional Arcane Power just by getting hit.  This effect is of most use to close-range Wizards, who will be taking more attacks than any other form of the class thanks to their tendency to ‘stick it out’ in melee when they can.  Still, it’s of use to the other forms of Wizard as well, who like the recovery perhaps even more than they want their initial Arcane Power pool big- after all, it only takes five hits to generate exactly the amount of Arcane Power you lost- anything after that is profit.  There are certain things to watch out for- it’s not clear whether standing in a damaging zone counts as a single hit for the entire time you’re in it, or if there are set time periods that will ‘tick’ off, and generally you’re not going to have time to analyze that mid-battle, so be wary there.

Pinpoint Barrier (25 Arcane Power): For the next 120 seconds, your maximum Arcane Power is reduced by 20 and your Armor is increased by 65%, and your chance of critical hits is increased by 5%.  You can only have one Armor active at a time.

You remember all those skills and runes where I pointed out you want to be good at critical hit chance in order to get the best use out of them?  This is part of that.  If you want critical hits, this is your Armor choice and you can ignore the others (Sadly, one of the Storm Armor options wants critical hits and you can’t have two armors at once.  Oh well.).  Outside of that case, you probably care more about one of the other rune effects.

Energy Tap (25 Arcane Power): For the next 120 seconds, your maximum Arcane Power is increased by 20 and your Armor is increased by 65%.  You can only have one Armor active at a time.

No, no, reread that.  There -is- a change.  Energy Tap makes Energy Armor into an increase to your maximum Arcane Power pool.  If you don’t care for the Absorption effect- and if you’re a long-range wizard you may well not care for it- this rune will give you far more Arcane Power to play with (ten hits worth, in fact, without having to get hit) than Absorption does- though that’s only at the start of each battle.  Alpha-striking Wizards will love this.

Force Armor (25 Arcane Power): For the next 120 seconds, your maximum Arcane Power is reduced by 20 and your Armor is increased by 65%, and any attack that would deal more than 35% of your maximum Life in damage, instead deals 35% of your maximum Life in damage.  You can only have one Armor active at a time.

This is a slightly quirky form of Energy Armor.  Theoretically, it can be good with a lack of Vitality and Life increases on your gear and a lot of Life Regeneration effects- but it’s hard to make it work out properly.  While a high-level Wizard can have very low Life, the speed at which you take attacks, even from bosses, will often overwhelm you no matter how quickly your Life orb refills if you try to rely on the damage reduction.  There’s probably a way to make it work, but it would take a lot more time and effort invested in it than is really worthwhile- so don’t worry about it.  If you don’t try to abuse it, this form of Energy Armor can occasionally still be useful in boss fights.

Prismatic Armor (25 Arcane Power): For the next 120 seconds, your maximum Arcane Power is reduced by 20, all your resistances are increased by 40%, and your Armor is increased by 65%.  You can only have one Armor active at a time.

Did you ever want to stand in Diablo’s red lightning and pretty much not care?  Prismatic Armor won’t let you quite do that, but it’ll let you come closer than virtually anything else in the game.  Increasing your already fantastic resistances (remember what I said in the description of the base skill?) by 40% of their value is incredibly strong.  You generally won’t want this as much if you’re a close-range Wizard, as more of the incoming attacks you face will be weapon attacks, but a long-range Wizard has a lot more concern about fireballs, venom sprays, and other elemental attacks than a close-range Wizard, so this rune can be very useful for them- assuming they don’t want Energy Tap instead (which is admittedly rare)