Went through twice this week, on hard and normal. You must get Crota to drop the sword by making the Thrall Necromancers to explode adjacent (next to) Crota. When it is dropped it is best for a Warlock to pick it up, and continue to the rocks to parkour (jump) their way up as far as possible. Doing this will help avoid the cyclone and I suggest everyone that is still alive does so as well. Now have the members of the team with out the sword switch to snipers/scout rifles. As you will notice Crota has now gone into a defensive mode and his shield is up. Crota will call forth Necromancer Witches (Wizards) now you must have three of your teams snipers shoot the Necromancer Witches. They must be suppressed as they shoot at you from down below. Now this is imperative that you do this part to the letter, have the remaining two snipers shoot Thrall Necromancers and get them to explode by Crota again. This will weaken his shield, the sword holder must jump over head of Crota and use the super to land directly on top to smash the remainder of the shield. Now everyone up top must shoot Crotas eyes for critical hit spot, while this is going on parkour your way up again if you have the sword. Enough critical hits and the eye will burst open. He will be pissed off and get his shield again. More Thrall and Witches will come and you must continue the steps. As Crota's eyes are all destroyed he will eventually be blind, at this point the Thrall and Witches will be in the largest numbers. Continue all the steps again and strike with the super, you will skip to a cutscene if done correctly. The player with the sword cuts off Crota's head, while other guardians defeat the last of the Thrall and Witches. The sword is then planted into to the ground and Crota's head is impaled on the sword. Then the end roll prizes appear on your screen. Congrats on beating Crota's end!