Rubra Rex

Rubra Rex, latin for Red King, more commonly known simply as Red, is a Arcturus Wolf owned by SPARTAN-013. It was initially adopted as a month old puppy abandoned on the streets of New Jerusalem on the world of Arcturus, where it had been abandoned by it's owners. It alerted him that the 'ONI Agent' escorting him was in fact a Necros Synth, he evaulated its usefullness to himself and brought the hound with him. Named after his red orientated coat, Rubra Rex was introduced to Bravo Company along with Ajax. The pup quickly took a liking to Bravo and seemingly took the Company as his pack and Ajax as the Alpha male. The other SPARTANS enjoyed the company of the animal and because of its large size, they could even play fight, resulting in stitches for both sides. As adulthood came, it often tried to upsurp Ajax as the alpha male, put was repeatedly but back by Ajax's 'tough love' attitude to Red. Though submissive to Ajax and incredibly responsive to his commands, Red awaits his chance to become the alpha male of Bravo Company. 
With the later introduced COs, he is somewhat wary, though gets on with Vincent Warren, Henry Rotilla and Cliff Highway and seems to show excessive adoration to Pandora Raina, who has mild Cynophobia. Surprisingly, he seems to respond to Joyeuse giving him commands and has a excessive fear of Fuu. He has a long running hatred with Warren's pet Royal Python, Victoria, whom he once tried to eat and realised his mistake via strangulation. 
Red has accompanied Bravo on several training operations, proving to be just as much a stealthy, stalking, predatory beast as the rest of the SPARTANs. He came with them during thier first mission, allegedly getting a higher kill count than some of his pack-mates. During WARDOG he was smuggled by members of Bravo. He acted as guard dog for Bravo's base, sensing things that could elude thier military sensor equipment and acted as point-hound during several infiltration, patrol and raiding missions, his keen senses giving the SPARTANS a clear tactical edge and his howls, thought to be just native wildlife by the Brutes, proved to be a effective signalling message for his comrades.
In combat, Red doesn't need anything more than sheer brute strength and animal cunning. Razor sharp canines mixed with savage claws, a hardy disposition, lightening reflexes and intense strength, along with his M9K Canine Armour make him a force to be reckoned with.