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

Jennifer Walters

Lawyer, Avenger

Super Strength, Super Speed, Agility, Stamina, Invulnerability, Intellect, Blast Power, Healing, Shape Shifter, Radiation, Unarmed Combat, Energy Absorption, Berserker Strength, Longevity

Relies on gamma-powered strength — occasionally uses Avengers tech

A-Force, A.R.M.O.R., Avengers, Avengers Emergency Response Squad, Book Law, Brides of Set, Cosmic Champions, Defenders, Fantastic Force, Fantastic Four, Fearsome Four, Future Foundation, Gamma Flight, Goodman, Lieber, Kurtzberg & Holliway, Heroes For Hire, Hulkbusters, HYDRA, Lady Liberators, Last Defenders, Legion of the Unliving, Magistrati, Marvel Balls, Punch Club, Renegades, S.H.I.E.L.D., S.M.A.S.H., The Initiative, The Vi-Locks, Thor Corps, Weapon X, Zombiotes