The main idea of this build is for Diamond Skin to absorb the majority if the damage you take, and with Force Armor reducing said damage to around 3k per hit (assuming your life is around 7k-9k, thought 4712 health is zero vitality and will allow Diamond Skin to absorb 13 hits) and Diamond Skin absorbing 20k+ damage, it usually takes around 9-13 monster hits (elite or normal) for Diamond Skin to fade. Now with Critical Mass paired with Venom Hydra and Venom Magic Weapon, you will have at maximum a 1-2 second cooldown on your defensive abilities, ie: Diamond Skin and Frost Nova. This means that by the time Diamon Skin expires, either after 6 seconds or taking 7 hits, the cooldown is already over and you can cast it again. It also allows for you to keep monsters almost perminantly frozen in place, which helps Venom Hydra because the pools of poison will remain in the same spot and stack, infinitely, and the monsters will remain frozen on the pools.
The main stats you want to focus on are Damage increasing stats; Intellect and Crit are main followed by Increased Attack Speed, ect. You also want stats that will help your life regenerate, for those rare occasions that you take health damage, this will prevent you from having to use potions regularly. So you want Health Regeneration and Life Steal as secondary to damage stats. Also, remeber, with this build you want to shoot for zero vitality be optimal (which is 4712 health), this will allow your Diamond Skin to absorb as many monster hits as possible.
Button 1 (left click)
Hydra (Venom Hydra) - Venom Hydra is practically a necessity in Inferno. It shoot 3 attacks that leave an AOE dot on the ground that STACKS, INFINITELY! This is extremely important for other parts of the build. I chose this as the main attack because it costs very little energy and you will almost always be able to cast it.
Button 2 (right click)
Arcane Orb (Obliteration or Tap the Source) - This is a nice main source of damage because you can studder step with it (ie: attack, run, attack, run, ect.). Kiting is necessary in Inferno for monsters that you can't freeze in place, so it's pretty necessary that your main attack spell is not a channeled spell. Depending on how often you find our self able to cast the skill will determine wether you want Obliteration (high damage, costs more) or Tap the Source (can cast more often because costs less)
Energy Armor (Force Armor) - This is the main reason that this build will work. For the unenlightened, Force Armor reduces all attacks that will damage your health more than 35% to damage your health by only 35%. If you have low life, around 7k-9k, you can reduce all monster damage to around 3k MAX damage, even less if you can get zero vitality, this is extremely necessary for this build to work.
Frost Nova (Bone Chill) - This skill can be slightly up to preference, but I find that Frost Nova helps a ton. Keeps monsters in the same place, so that way your Venom Hydra poison pools will stack and do massive AOE damage to all the monsters, also increases damage dealt by 15% by anything frozen. With this build, you will have virtually no cooldowns on any skills, including Frost Nova, so you can keep monsters frozen virtually 100% of the time.
Magic Weapon (Venom) - Venom Magic Weapon works extremely well with Critical Mass, every time you or your hydra shoot an enemy, all of the damage, on each monster, has a chance to reduce the cooldown on your spells by 1 second, since Venom Magic Weapon is a dot over 3 seconds, it continuously does this for the duration, making cooldowns almost non-existant.
Diamond Skin (Crystal Shell) - Another staple of the build. This works extremely well with low life (no vitality) and Force Armor. Force Armor reduces the damage by monsters to 35% of your life , which should be around 3k damage(if your life is low enough). With Diamond Skin absorbing 20k+ damage, it is able to absorb 9-13 hits (depending on how low your life is) before it is removed. Coupled with Critical Mass, you can keep Diamond Skin up virtually 100% of the time, which adds extreme survivabity in Inferno.
Critical Mass - This passive is necessary for this build to work properly. With Venom Hydra and Venom Magic Weapon, you will have virtually no cooldown on your skills like Diamond Skin and Frost Nova, depending on the size of the monster packs. The highest cooldown you'll see will be between 1-2 seconds.
Galvanizing Ward - Life regeneration is extremely helpful with this build. Diamond Skin will absorb the majority of the damage you take, however you may take damage to your life from time to time. This passive, coupled with life regeneration and life steal stats on your gear, will usually allow your life to regenerate back to full by the time your Diamond Skin duration is up, allowing you to save your potions only for absolute emergencies.
Glass Cannon - Since the damage you take is capped at 35% of your life from virtually every monster, this skill is a no brainer. 15% extra damage, and the build virtually ignores the negetive side effects.
Feel free to impart any insights or criticisms, I'm always looking to make my build better! Thanks for reading!