Kelos'vaarda-pattern storm rifle

The Type-55 Directed Energy Rifle/Advanced (T55 DER/A), commonly known as the Storm Rifle, is a Sangheili directed energy weapon.

Overview
Designed by Lodam Armory in the wake of the Great Schism, the T55 was in use by 2553 and saw use during Sangheili civil conflicts following the Human-Covenant War's conclusion. The T55 DER/A is considered to be a successor to and direct evolution of the widely used Type-25 plasma rifle; however, it is more similar to the Type-51 plasma repeater, itself an upgrade of the T25, in both form and function. The weapon features such modifications as a rotating modular coil set, a high-mounted cooling shroud, and an extended barrel, which improve upon the features of the standard plasma rifle it replaced the role of.

Despite their typical use of matériel dating back to the war with humanity, Sangheili in the reformed Covenant use the Type-55 as their standard-issue weapon. The SPARTAN-IVs deployed aboard the UNSC Infinity also use the Storm Rifle as part of their on-mission loadouts, despite it being of non-UNSC origin.

Changes from Halo 4 to Halo 5: Guardians

 * Fire rate increased. Time to overheat raised accordingly
 * More damage

Trivia

 * "Storm Rifle" is a literal translation of the German "Sturmgewehr", which is generally rendered as "assault rifle" in English, and is in fact the origin of that title. The StG-44 (roughly: Model 1944 assault rifle) was the first assault rifle to see widespread deployment during the latter part of World War II.
 * The Sangheili Ranger action figure will include a code that will unlock the "Chill" skin for the storm rifle.
 * Strangely, the Storm Rifle does not count toward automatic loadout weapon commendations in War Games, despite its predecessors all being considered automatic and its firing system being so.
 * The weapon's reticule is similar in both appearance and bloom behavior to the plasma repeater from Halo: Reach. The weapons' firing styles are also similar, though the Storm Rifle lacks the "fire through overheat" feature that the Plasma Repeater has. Presumably, it can be guess that the Repeater was the predecessor of the Storm Rifle.
 * It is possible to use equipment while the Storm Rifle is venting, which has lead to a tactic combining it with the Thruster Pack, whereupon the user fires till it overheats, jets to the side or in reverse to avoid incoming fire, then re-engages their target with the now-cooled weapon.

List of appearances

 * Halo: The Thursday War
 * Halo 4
 * Spartan Ops
 * Halo: Escalation
 * Halo 5: Guardians