Z-390 incineration cannon

The Weapon/Anti-Materiel Z-390 High-Explosive Munitions Rifle (W/AM Z-390 HEMR), also known as the incineration cannon, is a Forerunner anti-matériel weapon originally used to combat the Flood. It is commonly used by Promethean Knight Commanders.

Overview
The Incineration Cannon was often used to strategically purge infected sites. Prometheans used the Incineration Cannon when assaulting a location believed to contain a Gravemind, or early-forming spore mountains, that were deemed too small for ship weapons but too large for infantry weapons. The Incineration Cannon fires five antimatter-infused streams of concentrated explosive particles, which gather into globular projectiles that oscillate along a straight trajectory and disintegrate targets when landing a killing blow. The projectiles detonate and spread upon impact with a target, ricocheting and bouncing in tall but short arc trajectories. It initially holds five whole charges at a time with one shot per charge. Each charge is automatically "loaded" after firing and cool-down. It has been described as "mixing traits of a rocket launcher, shotgun, and flamethrower."

Design details
The weapon possesses an angular design and a metallic casing. It appears to be held together, at least partly, by energy fields as indicated by its self-assembly process and reloading mechanics. Red highlights can be seen while the weapon is self-assembling and throughout the casing once assembly is complete; these highlights grow brighter when the weapon is fired. The weapon features an integrated optical scope for targeting accuracy.

Variants

 * River of Light: The River of Light is an improved Incineration Cannon that was created during the Forerunner-Flood war, which led to many technical advances that ultimately proved fruitless. Upgraded with increased damage, a wider projectile trajectory, 25% increased battery capacity, faster charging speed, and faster heat dissipation, it unleashes long bursts of seven energy blasts if charged up. Available as an Ultra Rare REQ for Level 5 energy in Warzone simulations, the River of Light is also available as the third hidden weapon in the mission Reunion.
 * Heartseeker: The Heartseeker, carried by Warrior-Servants relentless on the hunt, is an advanced Incineration Cannon that fires slower-moving but more powerful energy charges with very strong homing behavior, 30% increased range, and a wider blast radius over the standard weapon. It is available in Warzone simulations as a Legendary REQ that costs Level 6 energy.

Changes from Halo 4 to Halo 5: Guardians

 * Power of the weapon is determined by how long the user holds down the trigger, with uncharged shots firing a burst of two projectiles with arcing trajectory and fully charged shots having a similar effect as those of the previous incarnation of the weapon, albeit without any secondary explosions. Keeping the weapon charged will slowly deplete its battery at a rate of 1% per second, similar to the Plasma Pistol.
 * Uncharged shot consumes 5% of each shot while fully charged shots mainly can consume up to 25% in total.
 * A battery meter replaces single-shot "magazines".
 * Lights on the weapon are recolored from red to orange.
 * Time between fully charged shots is shorter.
 * Ammo total reduced from 6 to 4 for fully charged shot and increased from 6 to 20 for uncharged shot.
 * Red reticle range significantly decreased.
 * No longer makes a sound when the player attempts to fire the weapon while out of ammo.

Halo: Spartan Strike

 * Carries a maximum of 8 shots.
 * Inflicts significant splash damage.
 * Can destroy a Wraith or Scorpion Tank in one precision shot.
 * Requires open area for safe use. As with other explosive weapons, splash damage at close range can injure or even kill the player.

List of appearances

 * Halo 4
 * Spartan Ops
 * Halo: Spartan Strike
 * Halo 5: Guardians
 * Halo: Official Spartan Field Manual