Diabolic Oculi

In the Demonology Warlock talent tree, Diabolic Oculi sits in the Diabolist hero talent tree, row 2 of 5. It is a single-point node.

Connected above

The tree draws a line into Diabolic Oculi from Diabolic Ritual.

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  Diabolic Ritual

  Spending a Soul Shard on a damaging spell grants Diabolic Ritual for 20 sec. While Diabolic Ritual is active, each Soul Shard spent on a damaging spell reduces its duration by 1 sec. When Diabolic Ritual expires you gain Demonic Art, causing your next Hand of Gul'dan to summon an Overlord, Mother of Chaos, or Pit Lord that unleashes a devastating attack against your enemies.

Connected below

Diabolic Oculi leads on to Looks That Kill.

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  Looks That Kill

  Your Diabolic Oculi now cast Diabolic Gaze at your primary demon's target every 1 sec while active. Fire a beam of destructive chaos magic at the target, dealing (80% of Spell Power) Chaos damage. Damage is increased by 100% per Demonic Oculus active.

Same row

Also on this row: Cloven Souls, Touch of Rancora and Secrets of the Coven.

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  Cloven Souls

  Enemies damaged by your Overlord have their souls cloven, increasing damage taken by you and your pets by 5% for 15 sec.

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  Touch of Rancora

  Demonic Art increases the damage of your next Hand of Gul'dan by 20% and reduces its cast time by 50%.

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  Secrets of the Coven

  Mother of Chaos empowers your next Shadow Bolt to become Infernal Bolt. Hurl a bolt enveloped in the infernal flames of the abyss, dealing (1347.3% of Spell Power) Fire damage to your enemy target and generating 3 Soul Shards.