Who Would Win?

Mephisto

Lord of a realm of Hell

Demonic Power, Reality Warping, Immortality, Soul Manipulation, Shape-Shifting, Energy Projection, Superhuman Strength

None (demonic power)

Hell-lords, Lords of the Splinter Realms; formerly manipulator of the Six-Fingered Hand

James Howlett

Adventurer, former soldier, spy, samurai

Super Strength, Agility, Stamina, Invulnerability, Healing, Weapon Master, Super Sight, Super Smell, Super Hearing, Implants, Feral, Unarmed Combat, Immortal, Escape Artist, Tracking, Swordsmanship, Animal Control, Enhance Mutation, Omni-lingual, Claws, Stealth, Berserker Strength, Leadership, Longevity

Adamantium-laced skeleton, retractable adamantium claws, X-Men uniform

Alpha Flight, Assassins Guild, Avengers, Avengers Unity Squad, Brotherhood of Evil Mutants, Central Intelligence Agency, Clan Akkaba, Confederacy of Dunces, Cosmic Champions, Dawn of the White Light, Defenders, Department K, Directorate X, Fantastic Four, Hard 7, Hearts of Darkness, Hellhunters, Heralds, Horsemen of Apocalypse, Howling Commandos, HYDRA, Jean Grey Academy, Landau, Luckman, and Lake, Marvel Werewolves, Marvel Zombies, Masters of Evil, Midnight Sons, New Avengers, New Defenders, New Fantastic Four, Nexus Beings, Opposition, Outlaw Avengers, Red Guard, S.H.I.E.L.D., Savage Avengers, Secret Defenders, Super Hero Squad, Swordbearers of Krakoa, Team X, The Black Legion, The Hand, The Lupine, The Marvels , The Pack, The Resistance, The Vi-Locks, Time-Plucked Titans, Weapon Plus, Weapon X, Weapon X-Men, Wolverine Squad, X-Force, X-Gene Mutant, X-Men, X-Men 2099, X-Treme Sanctions Executive, Zombiotes