Warlock builds

For solo questing to 60 with the Voidwalker tanking. You put Corruption, Bane of Agony and Siphon Life on a target, drain or Wrack while the pet holds it, and drain health back instead of eating. Demonology points keep the pet alive and quicker to resummon.

• Suppression and Improved Corruption come first: fewer misses and an instant, stronger Corruption.
• Improved Drains, Soul Siphon and Pandemic make Drain Life and Drain Soul hit and heal for more, and Soul Harvest adds mana regen after Drain Soul kills.
• Nightfall gives your DoTs and drains a chance to make the next Shadow Bolt instant.
• Wrack is the Affliction capstone: a channelled Shadow attack that also raises damage from your other Shadow DoTs.
• Demonic Embrace, Fel Vitality, Demonic Energies and Improved Voidwalker keep you and the pet healthy; Master Summoner makes resummons cheap.

For raid and dungeon damage with Fire and Shadow spells. You keep Immolate up, use Conflagrate and Shadowburn to keep both Shadow and Flame buffs running, and fill with Incinerate or Shadow Bolt. Demonic Sacrifice adds a lasting damage buff instead of keeping a pet out.

• Incinerate is the main filler and hits harder on targets with your Immolate; it requires Bane of Havoc, which copies some of your damage on other targets to the cursed one.
• Shadow and Flame links Conflagrate to Shadow damage and Shadowburn to Fire damage, and can keep Immolate from being consumed.
• Ruin raises the crit damage bonus of Destruction spells, and Agonizing Flames adds damage to all of them.
• Bane shortens Shadow Bolt, Immolate and Incinerate casts, and Cataclysm lowers their mana cost.
• Demonic Sacrifice of the Imp boosts Shadow damage and of the Succubus or Incubus boosts Fire damage, for 2 hours; Suppression adds hit chance.

Which demon to sacrifice depends on whether you fill mostly with Shadow Bolt or Incinerate.

For long single-target fights. You keep Corruption, Bane of Agony and Siphon Life up and channel Wrack, using instant Shadow Bolts when Nightfall procs. The Imp is sacrificed for a Shadow damage buff.

• Wrack is the main channel and raises damage from your other Shadow DoTs, and it requires Siphon Life.
• Soul Siphon adds Wrack and drain damage for each of your other Affliction effects on the target, so keeping all DoTs up matters.
• Pandemic and Malevolence let DoTs and drains crit harder and more often, and Shadow Mastery raises all Shadow damage.
• Nightfall procs from Corruption, drains and Wrack and make the next Shadow Bolt instant; Bane shortens hard-cast Shadow Bolts.
• Demonic Sacrifice of the Imp boosts all Shadow damage, which is nearly everything this build casts.

For battlegrounds and world PvP where staying alive matters as much as damage. You sacrifice one demon for its buff, then summon the Felhunter and keep the buff thanks to Demonic Pact, with Soul Link moving part of your damage taken onto the pet. Affliction points add Curse of Exhaustion and Nightfall.

• Demonic Pact keeps your Demonic Sacrifice buff when you summon a different demon, so you get the sacrifice and an active pet together.
• Soul Link sends part of your damage taken to the active demon and adds a little damage for both of you.
• Master Demonologist with the Felhunter out reduces Magic damage taken, and Improved Felhunter shortens Spell Lock's cooldown.
• Fel Domination and Master Summoner make a resummon fast if the pet dies.
• Curse of Exhaustion slows targets, and Improved Drains and Nightfall add sustain and instant Shadow Bolts.