They are the most epic heroes of our time, legendary heroes.................. popular Sci-Fi heroes. For Heroes not Heroines, that would be featured later. Equivalent to the Avengers team, just with firearms, not powers.
Master Chief: Sir I request a requisition Requisitions Officer: Of course Master Chief. Master Chief: I need 4,000 cases of explosives 10,000 large cases of ammo and 100 fuel cell generators (to recharge energy based weapons and or equipment) to start with. Requisitions Officer:....For what purpose Master Chief? Master Chief: Sir to finish this fight.
Well, technically, Clarke has Telekinesis and the ability to slow down his enemies, Prophet/Alcatraz has invisibility, superhuman strength, and armored skin, Shepard may or may not have Biotic/Tech abilities, The Chief and Six have energy shielding and superhuman strength/speed/agility/dexterity, and even Gordon's suit has a primitive shielding system. The only one to literally not have ANYTHING but his gun is Marcus.
Technically, by the time you play as Price in Modern Warfare 3, you're leading a two-man assault against a terrorist organization hiding in a hotel decked out in primitive powered armor, so by that game it's starting to branch a bit into science-fiction.