Nightfall

In the Affliction Warlock talent tree, Nightfall sits in the Affliction specialization talents, row 3 of 11. It is a single-point node.

Connected above

The tree draws a line into Nightfall from Unstable Affliction.

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  Unstable Affliction

  Afflicts the target with (417.3% of Spell Power) Shadow damage over 8 sec. Multiple uses of this ability may overlap. If dispelled, deals damage to the dispeller and silences them for 4 sec. This damage is increased by 15% per stack on the target. Generates 1 Soul Shards if the target dies while afflicted.

Connected below

Nightfall leads on to Improved Shadow Bolt or Drain Soul.

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  Improved Shadow Bolt

  Reduces the cast time of Shadow Bolt by 15% and increases its damage by 40%.

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  Drain Soul

  Drains the target's soul, causing (556.9% of Spell Power) Shadow damage over 5 sec. Damage is increased by 100% against enemies below 20% health. Generates 1 Soul Shard if the target dies during this effect.

Same row

Also on this row: Haunt and Shared Agony.

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  Haunt

  A ghostly soul haunts a single target, dealing (720.6% of Spell Power) Shadow damage and increasing your damage dealt to the target by 16% for 18 sec. While active, Haunt deals Shadow damage to its host and 1 enemies suffering from your Corruption or Wither. If the target dies, Haunt's cooldown is reset.

• 
  Shared Agony

  Increases Agony damage by 10% and Agony now hits another nearby enemy within 15 yds of the target.