Gear 5 is incredible, but Superman's power tier dwarfs the One Piece universe's scale.
Gear 5 Luffy can reshape reality with cartoon physics โ impressive and unique. But Superman operates at a power tier where planetary destruction is casual. The scale gap between One Piece and DC is enormous.
Luffy's rubber body would absorb Superman's punches, which is an interesting interaction. But Superman has heat vision (rubber melts), freeze breath (rubber becomes brittle), and the strength to simply throw Luffy into space.
Gear 5's Toon Force reshapes reality. Rubber body absorbs blunt force. Conqueror's Haki could theoretically affect Superman's willpower. The unpredictability is Luffy's greatest asset.
Superman's heat vision melts rubber. Freeze breath makes rubber brittle. Planet-moving strength and lightspeed movement operate at a tier above anything in One Piece.
Superman wins through overwhelming power from a higher-tier universe. Gear 5 makes this more interesting than most cross-universe matchups, but the power gap is too vast.
Monkey D. Luffy also fights
Superman also fights