Omni-Man's FTL speed and planet-cracking power narrowly exceed Gear 5 Luffy's impressive but lower-tier abilities.
Gear 5 Luffy with the Nika fruit is one of anime's most powerful characters โ he can reshape reality according to cartoon logic, stretch and transform his body in impossible ways, and has demonstrated island-to-continent level destruction feats. But Omni-Man operates at planet level with FTL speed.
Luffy's rubber body provides natural resistance to blunt force, which is Omni-Man's primary attack method. Viltrumite punches would be less effective against someone whose body absorbs and redirects impact energy. This gives Luffy a defensive advantage most opponents do not have against Omni-Man.
However, Omni-Man's speed exceeds Luffy's reaction time, and his attacks carry enough force to overcome rubber's energy absorption. Flying through Luffy at FTL speeds while generating planet-level kinetic energy would overwhelm the Nika fruit's defensive properties.
Gear 5 Luffy's Nika fruit reshapes reality, and his rubber body naturally counters blunt force attacks. His creative fighting style and toon-force abilities make him unpredictable and difficult to defeat conventionally.
Omni-Man's FTL speed exceeds Luffy's reaction capabilities, and his planet-cracking strikes generate enough force to overwhelm rubber's energy absorption. His durability means Luffy's attacks would need to be devastating to matter.
Omni-Man narrowly wins through superior speed and raw power, though Luffy's rubber physiology and Nika powers make this much closer than most Omni-Man matchups. The speed gap is the deciding factor.
Monkey D. Luffy also fights
Omni-Man also fights