The Bentusi are an old race in the galaxy
where the Homeworld
games, by Relic Entertainment
and the now defunct Barking Dog Studios, take place. They fly about the galaxy in gigantic vessels. Top-down, the ships are shaped like horseshoes, however from the side the ships are tall. The outside of their ships is grey and armored, the inside is a city, filled with light and activity.
In the original Homeworld, the Bentusi are first introduced approaching the Kushan as simple traders with very large inertia-less drive engines on their mothership-class ships. They act as arbitors for the Kushan, who in their exile have been forgotten by the galaxy, before the Galactic Council to secure their right of ownership to their homeworld. They are peaceful, intelligent beings, who use their influence to manipulate galatic politics. As a rule they do not actively engage in warfare, though their ships are armed with 4 heavy ion cannons.
Their first words to the Kushan welcome the younger race into the fold of all spacefaring races, the Unbound. This is a fairly straightforward definition for a title like "the Unbound," but it is changed in Cataclysm to fit the continuity.
In HW: C the designers of the game attempt to give more context to the Bentusi. To do so they retcon the title "Unbound" to fit the storyline involving the Beast. In the story a bio-mechanoid virus is released by the protagonists, it has the ability to subvert ships and use the biomass in them to make biocircuitry. The Bentusi are severely affected by this because they are by their nature part of their ships, "Unbound" by their bodies. When the beast takes over their ships it binds them to their bodies, a fate which they would rather die than got to.
In Homeworld 2 it is revealed that the Bentusi were reponsible for the spreading of limited Hyperspace Technology amongst the outer rim. They created a pax Bentus and were far more capable then to wage war on others. The rise of Hiigara, Taidan and other fledgling empires ended this pax, and the Galactic Council came about. A war began between the Hiigarans and Taidanii, a war which ended in a stalemate(or a dead heat) broken by the council. But a new ship was built by the Hiigarans with the newly discovered Hyperspace Core. A ship so powerful that it could easily turn the tide against the Taidan and it did. In so doing they brought the wrath of the Bentusi upon them, the great and terrible Bentusi armada wiped out the Hiigaran fleet and left them open to Taidan conquest. For this the Bentusi stripped themselves of weaponry. That conquest, the destruction and merciful exile of the Hiigarans was a blight upon the Bentusi, for they were unable to save so many and at once had lost a potential equal.