Can't go wrong with feral mammals

Wildcat- Wolverine

The second character cited above is Marvel Comics’ most significant breakout character since the 1960s, and emblemizes the prominence of the X-Men. A quasi-antihero who’d just as soon kill his opponents appeared to be what comic book fans wanted in the 1980s (the Punisher was soon to follow), and Wolverine has since been a cornerstone of Marvel’s line.

Consequently, the character has been overexposed since the early ‘80s, and the endless convolutions that have swamped his backstory and his doings in the past 25 years have neatly paralleled the problematic continuity of the X-Men franchise.

For a while, I thought that Arsenal or Cyborg (both actual Titans, after all) would be good matches for Wolverine. But a while ago, it occurred to me that Wildcat, DC’s own Joe Louis, is pretty much what the doc ordered. Obviously, he’s never been a Titan, but cheating on team lineups as such is what we do here! In any case, ol’ Ted has been a big player in the DC diaspora for the past decade or so, which suits me fine.

Commonalities:
Both have been shown to be virtually immortal (Logan’s healing factor prevents him from aging; Grant was imbued mystically with “nine lives”) and both are as implacable a combatant as anyone knows of in either universe. Both also have been shown to have heightened senses commensurate to certain animals.

Differences:
Logan is prone to beserker rages, and only occasionally exhibits the avuncular qualities that define Grant, who does not possess a skeleton and retractable claws laced with a fictional metal. Wolverine is also one of Marvel’s best-known properties, whereas only devotees of super hero fiction are aware of Wildcat.

Alternate histories:

WC: A mysterious, violence-prone man named Ted Grant is born in the late 19th century. His preternatural ability to recover from deadly adversity (his “nine lives”) ensures that he remains vital long past a normal human lifespan; he travels the world for many years as a soldier and mercenary. He becomes amnesiac and feral after World War II: Grant eventually is dragooned into the service of a government agency, for which he adopts the codename Wildcat. He rebels against the agency and is recruited into the Titans, where he befriends Changeling, is attracted to Donna Troy and bristles under Nightwing’s leadership. While Wildcat remains with the Titans to this day, he has lately joined the non-government sanctioned Justice League. Wildcat is recognized as one of the most deadly combatants on Earth.

WO: During WWII, a champion boxer known only as Logan is inspired to take the codename Wolverine in order to combat the Axis powers and various superhuman menaces. He joins the Liberty Legion during the war. His mutant "healing factor" sees that his aging is arrested, and for years afterwards, he’s recognized as one of the most formidable hand to hand combatants on Earth, and thus trains many newcomers to the super-hero community. While most of his wartime comrades grow enfeebled and perish, Wolverine currently mentors younger operatives in the revived Liberty Legion. He has also encountered various children who he has sired in absentia.