Hello guys, wanted to post this on the first day but totally forgot about it until today. Here is a video of just the final boss battle, we beat him in 7 mins after we found the right strategy and rhythm. Important thing to note is keep the sword bearer alive if you know Crota is going to move soon. Keep the sword bearer low and when you see Crota move, kill him and get the sword to ensure that Crota is staying in place and not moving. Enjoy!