So, first you have to go to the Divide. Then, go to that one spinmetal plant, then turn right. After that, you should find the cave disguised as a car. In the cave, you should find a chest with an exotic engram, and the item you need for the Ultima Blade quest. Further in the cave, Ganondorf spawns. Kill him to get a 1 hour time boost to speed up your builders. There should be a small crevice you can follow to fight Darth Vader. [spoiler]he is your father[/spoiler] After defeating him, a secret door will open that will allow you to fight the final boss. If you do it a certain way, you can unlock a cave on the moon allowing you to fight Krato and become the god of war.