Head to the left and jump to the next platform. Continue to the right and climb up the next set of ledges and right again over to another platform. Climb the ledges there and continue up and over. This part is pretty straight forward and you can easily see the path of ledges you need to take to keep continuing upwards. Once you get high enough, you will be at the colossus’s stomach. Work your way around the platform to get to his back and there will be a patch of hair there with a small blue vitality symbol. Stab it while you are hanging onto it and a scene will play showing you his hand come around to survey the damage. When his hand comes, jump from his back to the hand and try to stay on the palm part of his thumb. His hand will return to its position in front of him and when it is facing upwards, you will need to run down his arm and up to the next blotch of hair just below the collar there. This is the tricky part and is waaaay to easy to fall off here.

Be careful when running along his arm not to fall off since it is a long way back up. When you get to the hair patch, there will be another small blue vitality marker there. Stab it and his other hand will come over to inspect the damage. When the hand comes over, jump across to it and stab it and swing around to the back of it. The hand will carry you back to its original position and will lay out flat for you to regain some stamina. When it is flat, load up the sword and aim it at his left shoulder to uncover another vitality mark. Load up the bow and fire an arrow at it and hold on as his hand moves over to his shoulder. Once it is there, jump off his hand and onto his shoulder and up his neck to his head. This is where the final vitality symbol is located. His head will freak out from time to time, so make sure you jump down to his neck to regain stamina when you start to get low. A few stabs in the head of this final beast will finish him off for good.