Elites - Use a plasma pistol to take out its shields and use a headshot capable weapon such as a DMR, Needle Rifle, or Pistol to headshot it. Elites are tough enemies. Try to stay out of their fire until all the Grunts and Jackals are killed so you don't get shot in the back. Also, whenever possible, assassinate the Elite. Melee attacks are not recommended because they kill you in 1 one hit on Legendary. Brutes - For ones with energy shields, the best way to kill them is to use a plasma pistol to remove their shields and then use a Needle Rifle to supercombine which only takes 3 shots. For unshielded Brutes, Shotguns work well and so do Needlers and Needle Rifles. Hunters - The best thing to use against Hunters are Shotguns. Just run around them and shoot them in the back. If you can get them, Snipers are good too. Jackals - The DMR works well in killing them at long range. On Legendary, you will want to kill them with either long range shots or explosives. Jackal berserkers are the most dangerous of all Jackals and should be taken out first using headshots. Jackal shields on Legendary are nearly impossible to take down and melee will do no damage. Grunts - Grunts die best when you headshot them with a precision weapon. Drones - Drones are most susceptible to headshots but they are somewhat tough to pull off. However, the DMR is still the best gun to use on Legendary because the Drones take a lot of damage. Engineers - Any weapon will do. Overcharged plasma pistols do a lot of damage to them. [Edited on 09.23.2010 4:48 PM PDT]