First keep doging near the platform where Serg. Johnson is. His Beam Rifle will take down Tarturus's shields if he hits himm all 3 times. Next If you shoot him enough when his shields are down then he will say "Lucky Hit" Then continue to repeat. Watch out though because more brutes come to kill your guys(and you). One of these brutes has a shotgun. Use this when his shields are down. Shotguns, Needlers, and Plasma Rifles(not Brute Plasma Rifles though, they overheat too quick).

wait 4 the sniper 2 take his sheild down then shoot him.

Before you go into the room with Tartarus, go back to the room where you bust your friends out that had a few brutes in it. Get a fresh covey sniper from the foyer. Get on the spinning platform, no one pays you any attention from here. Aim at the crystal on tart's head to take his shields down in one shot, then another quick headshot, on an overheat, switch weapons and shoot. Sarge will also shoot him while his shields are down. The quickest way is with a Banshee, though.

duck

I must be a dumb a.. but i do not know how to get on top of the roof in zanzibar. I saw a guy crouch by one of the windows, next thing i know he jumped down and flew up onto the roof.... WTF, I can get up there with a plasma and by sword canclening i just cant do it like i saw that kid do it....

yes i'm having this problem as well :( Someone else on another site recommends using the carbine to take him down. To do this you need to stay on the middle level, and shoot...do not venture elsewhere while attacking him. When the Sargent says his shields are down, or when the white light (aura) dissapears then attack him with the sword or carbine, but take caution... good luck! -let us know if you have success, because i haven't yet :(

hey just keep doin wat ur doin but do it on co-op and get the other person to attack him with duel brute plasma rifles and if that dont work u can all ways take jonsens beam rifle. by wompas

to defeat him easily get near the end with johnson in the scarab and you have a banshee when he blows the door up park your banshee get out and shoot of the wings then get back in and fly through to tarturus and all it needs is a few shots with the main weapon the shoot him with the secondary plasma shot the green one(B) and he should be dead. if you can not get the banshee this far then get into the room where tarterus is and start to jump on to the platforms which circles the graverty lift lift and you should find on one of them a super weapon but it is hard to to since it is near the top at the highest point.

Make sure u have a beam rifle, u should get one in the earlier part of the level, and keep it. In the room before tarturus u can kill the brutes then pick up covenant carbine. Now in the room with tarturus jump on the HIGHER platform. u cannot fall off this platform, so it's safe. from here u can just wait for johnson to take his shield down and then shoot tarturus. U may get shot at by the other brutes that pop up but they are easy to take out. It can be done with just the carbine, but having the beam rifle gives u the extra cushion, just in case u run out of ammo. It's very easy to beat tarturus this way.

Alright first of all i know how you feel. After the fight with the before you jump on the platform leave the sniper rifle to the sgt your allies dont run out of ammo. when your elites go to get Tartarus you might as well watch. Stay away from close range weopons he will your ass. stay with your cov br but let the sgt take down his sheild.Go for all head shots and dont stick him make him walk over your nades repeat this process G.T. ZEBra cAKes

Alright first of all i know how you feel. After the fight with the before you jump on the platform leave the sniper rifle to the sgt your allies dont run out of ammo. when your elites go to get Tartarus you might as well watch. Stay away from close range weopons he will your ass. stay with your cov br but let the sgt take down his sheild.Go for all head shots and dont stick him make him walk over your nades repeat this process G.T. ZEBra cAKes

this how you kill tartarus onlegendary but you have to have a banshee. It sounds cheap but thats how i killed him. it took a couple a minutes but it works.