In a bare fist fight which means NO suits, NO powers and NO weapons. [spoiler]if you pick Guardian you lose[/spoiler] And since Chief is Human that means exos need not apply unless you want to give chief Cortana Some Spartan Traits that should be known: Incredibly fast reflexes that are impossible to chart and when adrenaline gets going time seems to slow down (Kelly Dubbed this 'Spartan Time') They can run at bursts of 55 kmh or 34.2 mph. Their skeletal structure is nearly unbreakable (their organs would get crushed before their bones) Incredibly strong (able to put a sizable dent into an early version of the MJOLNIR suit that out of all the permutations has the most armor and this was achieved with no power suit) Remarkably high pain tolerance (One even got his arm disintegrated by a fuel rod gun and didn't make a single noise)