From Halopedia, the Halo wiki
The Reaver is a bipedal anti-aircraft walker used by the Banished. The Reaver is capable of using its missiles as a propulsion system briefly in order to cover long distances or smash into enemies, similar to a Spartan's ground pound.
The Reaver is a relatively new addition to the Banished arsenal, and its manufacturer is unknown-though it bears telltale marks of both workshop and assembly vat construction, which hints at an origin on Doisac. They have largely replaced the Type-52 Anti-Aircraft Wraith and anti-aerospace fortifications in the Banished. The Banished deployed many Reavers against the crew of the UNSC Spirit of Fire on Installation 00 in March 2559.
Halo Wars 2
Reavers can be built at the Foundry by all Banished leaders. Reavers perform well against aircraft, but poorly against infantry, vehicles, and structures. In Blitz Reavers cost 60 energy and Prowling Reavers cost 80 energy. Prowling Reavers stay cloaked for 90 seconds.
List of appearances