Ravenus is an Autobot from the Armada portion of the Unicron Trilogy.
BLARRRRRRGH!
Ravenus was an Autobot who succumbed to addiction to Mini-Con Powerlinx energy. Captured by agents of Unicron, he was further warped and mutated, his mind decayed, until he was little more than a slavering beast that Unicron's minions used as a tool.
Even before he was corrupted, it seems Ravenus had little in the way of brainpower.
Fiction
Micron Legend: Linkage Mini-Comics
Me look familiar. Where me seen me before?
Ravenus' Powerlinx command was greatly enhanced, so that it triggered the servility programs within any Mini-Con within earshot, forcing them against their will to Powerlinx with him. He carried the Doomstone inside him, and the powerful dark energies of that gem would be chanelled through the mental link formed by a Powerlinx into the Mini-Cons' Linkage soul-dimension, destroying it, and with it, the Mini-Cons' minds and free wills. However, he was stopped by the newly-upgraded Mini-Cons Redline and Kingbolt, and the Doomstone safely extracted from him. He would have been destroyed, but Twirl, the Mini-Con he had captured, had found out through the Powerlinx that he was an Autobot under that warped exterior, and begged her friends to help him. The Mini-Cons used their new powers to reverse the mutations and return Ravenus to his original form.
When the Mini-Cons of Earth rejoined the Autobot forces on their way to Cybertron, Ravenus went with them, and fought against the hordes of Unicron drones in order to atone for his time as one of the Chaos-Bringer's minions. Even though Twirl underwent the upgrade that broke the servility program bonds, she seemed to remain close to Ravenus, and the two fought side-by-side.
Ravenus' fate after the battle with Unicron is unknown.
Toys
No toy of Ravenus was ever produced, though both of his forms were based on existing toys. His "mutant" form uses the Armada Terrorsaur toy as a model, in varying shades of black, deep green and tan. His original Autobot form is based on the Diaclone coloration of the toy that would become Generation 1 Swoop, following the Armada cartoon's tradition of using character models from previous series as extras.
Linkage author/illustrator Hirofumi Ichikawa had proposed that Takara make a Ravenus toy as a special mail-away premium, perhaps with proof-of-purchase of the entire Micron Legend DVD series, but the proposal never went beyond that stage.
(It is worth noting that according to Mr. Ichikawa, Ravenus is not intended to be an "alternate" UT incarnation of G1 Swoop. It is also highly unlikely he is related to the Energon character Swoop, as even before he was mutated, his name was "Ravenus" and continues to be so even after he is restored to his original form.)