Mastermind

In the Shadow Priest talent tree, Mastermind sits in the Shadow specialization talents, row 7 of 11. It takes 2 points to fill. Its row opens once 8 points are spent in Shadow Talents.

Connected above

The tree draws a line into Mastermind from Maddening Touch, Dark Thoughts and Shadowfiend.

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  Maddening Touch

  Vampiric Touch deals 20% additional damage and has a chance to generate 1 Insanity each time it deals damage.

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  Dark Thoughts

  Increases the chance for Shadowy Insight to occur by 25%. When consuming Shadowy Insight, Mind Blast generates 1 additional Insanity.

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  Shadowfiend

  Shadow Word: Death has a 40% chance to summon a Shadowfiend for 5 sec when damaging targets below 20% health. Summons a Shadowfiend to attack your target for 5 sec. Generates 1 Insanity each time the Shadowfiend attacks.

Connected below

Mastermind leads on to Mindbender and Deathspeaker or Death and Madness.

• 
  Mindbender

  Casting Voidform summons a Mindbender for 10 sec. Summons a shadowy fiend to attack your target. Generates 1 Insanity each time the Mindbender attacks.

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  Deathspeaker

  Shadow Word: Death damage increased by 25%. Shadow Word: Death gains its damage and talent bonuses against targets below 35% health instead of 20%.

• 
  Death and Madness

  If a target dies within 7 sec after being struck by Shadow Word: Death, generate 8 Insanity. When Shadow Word: Death fails to kill a target below 20% health, its cooldown is reset. Cannot occur more than once every 10 sec.

Same row

Also on this row: Subservient Shadows, Mind's Eye or Distorted Reality, Spectral Horrors and Instilled Doubt.

• 
  Subservient Shadows

  Summoned minions last 20% longer and deal an additional 15% damage.

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  Mind's Eye

  Reduces the Insanity cost of Shadow Word: Madness by 5.

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  Distorted Reality

  Increases the damage of Shadow Word: Madness by 20% and causes it to deal its damage over 12 sec, but increases its Insanity cost by 5.

• 
  Spectral Horrors

  Shadow Apparitions deal 30% increased damage to targets affected by your Shadow Word: Madness.

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  Instilled Doubt2 ranks

  Increases the critical strike chance of Vampiric Touch and Shadow Word: Pain by 8% and their critical strike damage by 20%.