Halo because the covenant is actually more brutal for example, they freaking glass planets. And the fallen? They just scavenge earth, moon, Venus and look for "Guardians" to kill. And like I said the covenant actually destroy ****! And also they look more menacing.

This isn't even an argument. Halo would win on raw numbers alone, nevermind their superweapons, manuverability, and straight up firepower. There's only one Harbinger left, and unless I read the grimore wrong, they won't use it because they need it to make more Harbingers to keep for later. And that's if the Reef decides to partake in this fight. If they don't, and just go silent and hide, all of Earth could be glassed in a day with no resistance.