Halo 2 > Halo 3 > Halo 3 ODST > Halo Reach > Halo CE
Based on campaigns.
Did you know that brutes can kill each other with one punch because a nrute can take 2 pucnhes from a spartan and a spartan can take 2 punches from another spartan and a brute is twice as strong and can kill a spartan with one pnch which means they can kill nother brute with one punch