Cluster Arrow

Cluster Arrow is a  Archery skill in Diablo III. It bears some resemblance to the classic Amazon skill Exploding Arrow.

In-game
Fires an exploding arrow that detonates at the targeted location (not enemy), bypassing most types of obstacles, including enemies, but not the walls (including those placed by Waller monsters). This hits almost instantly and does not count as a missile.

Cluster Arrow has a very long range, about 120 yards (for player, it means that any location within screen borders can be hit, and Cluster Arrows shot by Sentries can reach the target even if those were left behind).

The primary explosion causes high Fire damage within 10 yards and releases 4 grenades that explode for average Fire damage within 6 yards each. These grenades may, but are not guaranteed to, intersect, so it may be hard to hit the same enemy with more than one grenade.

Runes

 * Dazzling Arrow: damage type changes to Lightning, all enemies hit by the grenades are Stunned for 1.5 seconds, and damage of grenades increases to 250%.
 * Shooting Stars: damage type changes to Physical, no longer drops grenades, but releases 2 rockets hitting for 600% damage as Physical each.
 * Maelstrom: damage type changes to Cold, no longer drops grenades, but releases 3 rockets that each deal 450% damage as Cold and heal the Demon Hunter for 2% of maximum Life per enemy hit.
 * Cluster Bombs: arrow turns into a slow bomb that drops six small grenades in a straight 35 yard long line, each exploding for 650% damage as Fire within 6 yards. In the end, the bomb also explodes for 650% damage as Fire within 10 yards. Note that for the sake of Grenade-enhancing skills and items, the bomb itself also counts as Grenade.
 * Loaded for Bear: damage of the primary explosion increases to 850%, and damage of grenades to 250%.

Non-rune enhancements

 * Manticore (Legendary Crossbow): Cluster Arrow deals 250-300% more damage and costs 50% less Hatred.
 * Bombardier's Rucksack (Legendary Quiver): Cluster Arrow deals 150%-200% increased damage.
 * Hellcat Waistguard (Legendary Belt): Grenades fired by Cluster Arrow, as well as the Cluster Bomb, have a chance to bounce 3-5 times, dealing additional 50% damage on each bounce, increased to 800% on the final bounce.
 * Embodiment of the Marauder Set (Set Bonus for 4 items): any time the Demon Hunter fires Cluster Arrow, all of their Sentries will fire it as well at their current target, fully benefiting from runes and enhancements.
 * Embodiment of the Marauder Set (Set Bonus for 6 items): for every active Sentry, damage of the Demon Hunter's own Cluster Arrow increases by +12000%.

Passives

 * Grenadier: blast range of the minor grenades increases by 20% and damage by 10%.
 * Ballistics: Damage dealt by rockets from Maelstrom and Shooting Stars is doubled.