Warzone Firefight (gametype)
From Halopedia, the Halo wiki
Warzone Firefight is a Warzone gametype variant in Halo 5: Guardians which acts as a spiritual successor to Firefight from Halo 3: ODST and Halo: Reach , which was released as part of the Warzone Firefight content update on June 29, 2016, with a public beta having been previously available between April 14–19, 2016. Up to eight players work together to complete five rounds of increasingly difficult, dynamic objectives set against a timer. Warzone Firefight also includes a new tier of Mythic enemy bosses, even more difficult to defeat than the Warden Eternal. Like Warzone and Warzone Assault, players have full access to their REQ collection for use against enemies.
There are three variants of Warzone Firefight: Heroic, Legendary, and Mythic (which is not always available), each facing enemies and bosses tuned to said difficulty level; Mythic enemies are Legendary enemies, except faced in much greater numbers, along with skulls added in. Legendary and Mythic have a 1.25x and 1.5x score multiplier over Heroic, respectively.
There are five rounds that are five minutes long. Each round has a certain task that must be completed in order to advance. After each successfully completed round, the respawn timer is upped by five seconds, starting from 10 seconds, and ending at 30 seconds during the final round. The fifth round is usually a boss rush-esque round, with various Legendary bosses spawning at the start of the round, culminating in a fight with one or more Mythic-tier bosses. If the task at hand fails to be completed when the timer expires, or the target to defend is lost before the time expires, the match ends. If all tasks are completed, the match is completed.