By taking skills that have large Mana costs and runes that restore Mana, in addition to passives that improve Mana pool efficiency and boost damage, the point of a Mana Fund build is to deal out as large an amount of damage as possible while sustaining the attack for as long as possible. While there are many ways to achieve this, this build presents one possible setup.
Primary Skill: Plague of Toads (Explosive Toads)
Secondary Skill: Locust Swarm (Searing Locusts)
Defensive Skill: Horrify (Ruthless Terror)
Terror Skill: Soul Harvest (Soul to Waste)
Decay Skill: Acid Cloud (Corpse Bomb)
Voodoo Skill: Big Bad Voodoo (Rain Dance)
Passive Skills: Spiritual Attunement, Pierce the Veil, Blood Ritual
By combining Spiritual Attunement, Pierce the Veil, and Blood Ritual, this build sets itself up to spend slightly more Mana and some of its Life, while possessing and regaining more Mana than normal. That kind of Mana accelerating provides fodder for a very expensive way of combat, which directly permits abuse of high-cost skills like Acid Cloud and Plague of Toads. For both of these skills, the highest-damage form has been selected- in Acid Cloud’s case, this is also because Corpse Bomb does all its damage at once, making it an even more immediate damage-generator, and causing it not to care much at all about enemy positioning. Big Bad Voodoo makes things even worse, particularly with Rain Dance to keep the Mana-generation up. If you find that you’re producing plenty of Mana to spend without Rain Dance, go ahead and swap it for Jungle Drums to make the damage-dealing capability even stronger.
Horrify is used to provide an occasional mana surge and keep enemies off your back, since you lack protection and other ways to stop nearby enemies from laying into you, though Ruthless Terror can be swapped for Frightening Aspect if the defense boost is more important to you or you just don’t need the extra mana. Similarly, Soul Harvest has its duration boost on so that you can keep a greatly heightened Intelligence- thereby further improving the damage you deal with Corpse Bomb.
Cloud of Locusts is in Burning Locusts mode for maximum damage- if you are finding that it doesn’t spread well enough because enemies die while not clustered up, then Haunt (Lingering Spirit) will be your preferred option and give you a nice available extra damage boost. As with the prior two theorycrafts, this is an example of how Witch Doctor passive skill selection will often shape the choice of active skills- and in this case, it’s not as directly altering the choice as the other examples: there are a lot of other possibilities here, I just chose to focus on Corpse Bomb as the build’s form of raw damage. Firebats or Lob Blob Bomb versions are quite possible as well, as are likely several others that I haven’t considered yet.
