Unlike previous installments of the game, Diablo 3 features a different resource system for each of its five classes: Barbarian, Demon Hunter, Monk, Witch Doctor and Wizard. Only one of these classes has the “classic” mana as a resource now, and this post will give you an overview of the variety of resources Blizzard introduced in D3.
Barbarian – Fury
Barbarians attacks are powered by Fury resource. It’s gained by killing enemies and taking damage. Unless you’re using the “Unforgiving” passive skill available at level 55, your Fury will deplete over time when you’re not in combat. Some of Barbarian’s primary attacks such as “Bash” or “Cleave” generate fury, but using more potent skills will deplete it.
Demon Hunter – Hatred & Discipline
Demon Hunter uses a system combining two different resources, and is the only class that does so. The first one is called Hatred, and your basic attacks generate it and more powerful offensive attacks expend it. Hatred starts at a value of 150 and regenerates by 4 points/second, not including the use of any abilities or passive skills.
The second resource is Discipline, and it has a default value of 30. The regen rate is 1/second. Discipline is used by defensive spells: basically anything that helps you survive or get away from enemies will use Discipline.
Monk – Spirit
Monk’s resource is called Spirit. It works similarly to Barb’s Fury: several of your primary attacks generate Spirit, while most others deplete it. Unlike Fury however, Spirit does not degenerate over time but instead it actually regenerates in the same way as Mana or Hatred. Monks have a decent number of abilities, ability combos, skill runes, passive skills and even items that can improve the regeneration rate of Spirit.
Witch Doctor – Mana
Surprisingly only one class in Diablo III uses Mana as a resource, and that is the Witch Doctor. It works exactly like in previous Diablo games or any other RPG game for that matter: it regenerates over time, and casting spells costs a certain amount.
Wizard – Arcane Power
Arcane Power is quite similar to Mana: it has a fixed amount of 100 (able to increase this by 20 through passive skills called “Astral Presence” though). It also regenerates by 10/second, or 12 if you use the aforementioned “Astral Presence” passive. Most of Wizard’s spells cost around 15-25 Arcane Power, so you can use a few before you run out of AP. However, Wizard has a lot of spells that have no costs at all to cast, so you need to constantly rotate these in order to make use of Arcane Power’s natural regeneration rate. Some of these so-called “Primary” spells can also replenish Arcane Power each time they hit an enemy, for example “Magic Missile“, a spell available at level 1 has an “Attunement” skill rune that gives you 4 AP each time you cast it.
Many old Diablo 2 and new players have been a bit confused about this stuff, so I do hope this post helped explain you the difference between these five resource systems in Diablo 3.