Who Would Win?

Henry Philip McCoy

Scientist, X-Men member, former Avenger, diplomat

Super Strength, Super Speed, Agility, Stamina, Intellect, Healing, Super Sight, Super Smell, Super Hearing, Feral, Unarmed Combat, Gadgets, Claws, Pheromone Control, Stealth, Berserker Strength, Leadership

X-Men uniform, various scientific inventions

3K, Avengers, Avengers Unity Squad, Brotherhood of Evil Mutants, Defenders, Doc Fantastic and his Five for the Future, Exiles, Illuminati, Jean Grey Academy, Opposition, S.W.O.R.D., Secret Avengers, Shadow-X, The Initiative, The Six, U-Men, X-Club, X-Factor, X-Force, X-Gene Mutant, X-Men, X-Punks, X-Terminators, Xavier Institute

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