The reaver evolved from a civilian mobile manufacturing unit that was militarized to become a mobile artillery piece, ensuring that fewer lives would be lost when assaulting enemy bases. Somewhat fittingly, reavers are renowned for leveling entire colonies in moments.
The reaver itself does not mount any weaponry, but instead houses a micro-manufacturing plant similar to the carrier, producing tiny robotic drones known as scarabs.
Scarabs are small, highly explosive drones constructed and launched by reavers. They are launched at enemy targets and installations in groups, able to level enemy structures in moments. Unlike interceptors however, Scarabs do not return to the reaver. Instead, they explode on impact, generating devastating electromagnetic fields that cause heavy damage to their targets.
The following section contains information from a previous version of StarCraft II which is no longer valid.
The reaver made a brief appearance in StarCraft II promotional material. However, it was removed from the BlizzCon 2007 build of the game. Its role as a siege unit was given to the colossus, which possesses superior mobility and hit points and occupies the same position in the protoss tech tree as the reaver.
It was meant to be produced from the robotics facility and required a null circuit before it could be warped in. A replacement for the reaver was being sought in July 2007.
The reaver was meant to appear in the StarCraft II: Wings of Liberty campaign and in the map editor, but was not present at release.
↑The Firebat and Reaver will be in the single player campaign and will both be in the Map Editor as well. The Lurker will be in those as well as multiplayer. Karune. 2009-04-23. Unit Question!!!!!!!Battle.net StarCraft II General Discussion Forum. Accessed 2009-04-24.