Who Would Win?

Galan

Devourer of Worlds, cosmic entity

Flight, Super Strength, Super Speed, Stamina, Invulnerability, Telepathy, Telekinesis, Intellect, Teleport, Psychic, Force Field, Blast Power, Healing, Magic, Super Sight, Super Hearing, Phasing / Ghost, Feral, Psionic, Power Suit, Radiation, Unarmed Combat, Gadgets, Weather Control, Divine Powers, Siphon Abilities, Size Manipulation, Immortal, Tracking, Astral Projection, Possession, Probability Manipulation, Super Eating, Energy-Enhanced Strike, Light Projection, Reality Manpulation, Levitation, Matter Absorption, Dimensional Manipulation, Enhance Mutation, Omni-lingual, Energy Shield, Siphon Lifeforce, Gravity control, Illusion Casting, Earth Manipulation, Genetic Manipulation, Time Manipulation, Power Item, Death Touch, Energy Absorption, Energy Manipulation, Cosmic Awareness, Willpower-Based Constructs, Energy Based Constructs, Berserker Strength, Leadership, Longevity

Worldship Taa II, Ultimate Nullifier, Elemental Converter, heralds

Cosmic Champions, Eternity Watch, Great Powers of the Universe, Proemial Gods, The God Squad

J'onn J'onzz

Detective, Justice League member

Shape-Shifting, Telepathy, Superhuman Strength, Flight, Intangibility, Invisibility, Martian Vision, Regeneration

Martian technology (rarely used — relies on innate powers)

Darkstars, Justice League of Aliens, Justice League Of America, Justice League Task Force, Justice League Unlimited, Martians, Outsiders