Sentry

Sentry is a Device skill for the. The concept is loosely based on Assassin's Sentinel Traps.

In-game
The stationary turret is placed within 60 yards, at the cursor location. The fire is completely independent, and Sentries may not be attacked, only being destroyed if the Demon Hunter dies. Turret fire has zero Proc Coefficient. A buff icon displays the number of Sentries a character has active.

It is one of seven skills (along with Overpower, Dashing Strike,, Blood Rush with Metabolism rune, Avalanche with Tectonic Rift rune, and Furious Charge with Dreadnought rune) that uses a Charge system, allowing multiple casts to be performed in a single cooldown period if enough charges have been accumulated. The charge replenishment time is treated as a cooldown, and reduced accordingly.

Sentries have very small (but still tangible) collision size, and therefore may not effectively block enemy pathing.

Runes

 * Spitfire Turret: The turret will also fire homing rockets at random nearby enemies for damage as Fire. Damage type of the bolts changes to Fire (unlocked at level 28).
 * Impaling Bolt: Damage type changes to Lightning, and the bolts now pierce through enemies (unlocked at level 36).
 * Chain of Torment: Turrets no longer fire; Instead, chains form, both between Sentries and between the Demon Hunter and each Sentry. Chains deal damage as Physical every tick to each enemy they touch. Chains have a maximum range of 40 yards each (unlocked at level 45).
 * Polar Station: Damage type changes to Cold, and the turret also chills nearby enemies (16 yards radius) by (unlocked at level 52).
 * Guardian Turret: The turret also creates a shield that reduces damage taken by nearby allies (20 yards radius) by, effect from multiple Sentries does not stack (unlocked at level 60).

Non-rune enhancements

 * Bombardier's Rucksack (Legendary Quiver): Increases Sentry damage by 75–100%. Increases the maximum number of Sentries (not charges) at one time by 2.
 * Embodiment of the Marauder Set (Set Bonus for 4 items): Increases Sentry damage by +400%. Whenever the Demon Hunter uses Elemental Arrow, Cluster Arrow, Multishot,, or Chakram, all of their Sentries fire it as well at their current targets, fully benefiting from runes and enhancements.
 * Embodiment of the Marauder Set (Set Bonus for 6 items): For every active Sentry, damage dealt by Companions,, the Demon Hunter's Primary (Hatred generator) skills, Elemental Arrow, Cluster Arrow, Impale, Chakram, and Multishot increases by +12000%.
 * Helltrapper (Legendary Hand Crossbow): Chance on hit to summon a Sentry.
 * Tasker and Theo (Legendary Gloves): Sentry attack speed increases by 40-50%.
 * Enforcer (Legendary Gem): Increases damage by 15% (+0.3% per rank).

Passives

 * Numbing Traps: Enemies hit by Sentry fire deal 25% reduced damage for 5 seconds.
 * Custom Engineering: Doubles the duration of Sentries (to 60 seconds). Also increases maximum number of Sentry charges from 2 to 3, and increases the maximum number of Sentries at a time by 1 (normally to 3).
 * Ballistics: Damage dealt by rockets from Spitfire Turret is doubled.