Wolverine's past remained a mystery in Marvel Comics for decades. Although as the X-Man's backstory was uncovered, piece by piece, the truth was far more difficult to grasp for Logan and his allies. As those clues were teased out, a prominent enemy resurfaced from Wolverine's early days -- a sinister figure who's also one of his few biological family members.
Dog Logan was perhaps the first adversary Wolverine (aka James Howlett) ever had, a vengeful half-brother with plenty of dangerous skills of his own. And, unlike Sabretooth, Dog's attacks had a genuine effect over the years, which grants him real power over Wolverine.
Wolverine's Brother, Dog Logan, Brought Out His Dark Side
Dog Logan debuted in Wolverine: The Origin, the 2001-2002 series by Paul Jenkins, Bill Jemas, Joe Quesada and Andy Kubert. Born in the late 19th century, Dog was the son of Thomas Logan, groundskeeper of the wealthy Howlett estate.
Although he developed a bond with James Howlett and his friend, Rose, Dog was verbally and physically abused by his father. Consequently, Dog grew up to become brutal young man whose horrendous actions led to his father's firing. In an act of pure rage, Thomas murdered James' father, John Howlett. After witnessing the brutal act, James unsheathed his claws for the first time, killing Thomas and scarring Dog with a slash across the face.
Years later, Dog was hired to hunt down James Howlett and Rose. He quickly beat an exhausted James and dredged up his foggy memories of the traumatic night of the killings. And in turn, Dog revealed that, not only were he and James half-brothers, but that James' mother had killed herself. Those shocking truths threw James into a berserker rage, and in the ensuing chaos, Wolverine accidentally killed Rose. James ventured into the woods, and away from humanity, to embrace his animal side. In short, Dog is to blame for the future Wolverine became a more animalistic figure.
How Wolverine's Brother Dog Logan Joined the Modern Marvel Universe
Dog spent years hunting down his half-brother, and later followed Wolverine into the present-day, due to the time-travel shenanigans at the center of Astonishing Spider-Man and Wolverine. Dog was finally able to make his move in Wolverine & the X-Men #25, by Jason Aaron and Ramon Perez. He briefly served at the Hellfire Academy, but was last seen jumping into the Siege Perilous, refusing the possibility of reconciling with his brother.
During his time at the Hellfire Academy, Dog even had the chance to meet Sabretooth, and was notably unimpressed with Wolverine's longtime nemesis. Dog's disappearance is one of the bigger mysteries still lingering from the era of the Jean Grey School. Kade Killgore, who went through the Siege Perilous with Dog, has been a consistent presence in the modern era as one of the leaders of Homines Verendi, the chief enemies of the Marauders.
However, Dog's whereabouts remain a genuine mystery, and a potent one at that. As Wolverine's brother, his understanding and experience with Logan make him a valuable and dangerous asset to be deployed against the formidable X-Man.