|Given name||Rob Cain|
|Species||Terran; Type C Cyborg|
|First Anime appearance||"Outlaw World"|
- Clyde: "You're "Death" Rob?!"
- Rob Cain: "Some people call me that."
- —Outlaw Star, "Outlaw World"
Rob Cain was a notorious killer who earned the nickname "Death" for killing over thirty people in his lifetime. His partner was assumed to be his brother, Butch. When his brother visited Sentinel III, he started a brawl in a local man's bar, which resulted in his death at the hands of would-be outlaw, Gene Starwind.
Cain eventually caught wind of his brother's death and headed for Sentinel III. His intention was to avenge Butch by finding and killing the man who killed him.
Upon arriving at Clyde's Bar, he scoped the area out, asking Clyde outright if he knew a man named "Gene". Clyde feigned ignorance, providing only vague answers to Rob's questions in regards to Gene's involvement in the death of Butch. When Gene finally chose to face him, Cain found it hard to believe that his brother had been killed by a "runt" like Gene.
In kind, Gene insulted his brother by calling him a "wimp" he made good money off of. Angered by Gene's flippant behavior, Cain declared that Gene would be the thirty-first person he killed. Gene, undaunted by the threat, insulted Cain, mocking his nickname instead.
Cain attempted to attack Gene, but Gene shot the man. Undaunted, Cain recovered and taunted Gene, suggesting that he was a coward without a gun. Gene shot Cain in the head, but the man remained on his feet. He was eventually killed by Gene when Jim Hawking revealed he was a Type C cyborg.
Rob Cain is a man with dark brown skin and long, brown hair. He bore a noticeable scar on his bottom lip. While on Sentinel III, he swore a gray shirt and a long, brown coat.
Rob Cain was a man who took pride in his profession as a killer. The vague reveal of his identity was enough to shock the likes of Clyde, suggesting a was widespread reputation on the frontier. Arrogant and self-assured, he underestimated Gene Starwind's strength based on appearance and bias toward his brother's abilities alone.
As a cyborg, Cain uses a mass of sharp, metal tentacles concealed by his right-hand glove and jacket sleeve. In addition, he demonstrates a noticeable resistance to being fatally wounded with bullets. The impact of the bullets can cause him to lose his balance, as shown when he is brought to the floor after being shot multiple times in the chest. When being shot in the forehead forces his head and neck to snap backwards, he is able to recover fairly quickly after being shot and shows no indication that his fighting skills are negatively affected.
- Rob Cain is the first character Gene is seen fighting.
- Gene insults him by calling him "Deaf Rob".