Benefactor

The Benefactors are an alien species appearing in Greg Bear's The Forge of God and Anvil of Stars. They save species from hostile von Neumann probes and destroy those responsible for sending them. In this way, they enforce the Law, a policy of deterrence against the creation of such machines.

Description
The appearance and biology of the Benefactors is not known. They seem to interact with other species only through robotic intermediaries. During the Earth's final months, they interacted with humans only as mechanical spiders, which they used to preserve selected cultural and biological samples as well as humans. When transporting survivors of destroyed worlds, they present themselves as simplistic, bronze-colored, robotic versions of the species in question. For instance, they appeared to humans as limbless, faceless humanoids, while they interacted with the Brothers as long chains of metallic spheres.

History
The Benefactors deliberately do not mention much about their history, but are known to have had a violent civil war at some point. Due largely to this experience, they subscribe to and enforce the Law, which states that any civilization that produces self-replicating planet killers must be hunted down and destroyed by their victims.

The Benefactors encountered the Red Tree Runners around 2,000 BCE and set up a peaceful relationship. When the Killers attacked the Red Tree Runners, the Benefactors assisted them in fending off the attack and preserving their home worlds, although the Red Tree Runners still suffered enormous casualties. Afterward, the Benefactors constructed a Ship of the Law for the Red Tree Runners and sent them on an ultimately fruitless mission to find and destroy the Killers.