If you don’t have other options and/or don’t want to invest more time, you can completely cheese both phases of the boss. Check out some YouTube guides on Calus cheese, but here’s the rundown below 👇 Make sure to pick up strand with a grapple grenade! For the first half, you’ll climb under the stairs near where the rally flag is. Don’t start the encounter until you’re down there! Make sure to equip weapons that can still hit him with the stairs slightly in the way. No explosive weapons (like rockets or gls) or bows. Fire away at him until he’s nearly into the second phase. Machine gun and auto rifle work well. Before phasing him, climb out from under the stairs. This will take some effort and feel a bit risky. Use your grapple if you need. Next, wait until your grapple is back. Then, stand on a box near the rally flag. You want to be outside the area Calus encloses. Then, when the walls of the arena form and it says “joining allies,” you’ll grapple towards the top of the arena on top of the walls. Once you reach the top, you’re able to shoot through the walls and hit Calus with ease. Shoot him until he dies and the walls of the arena will fade, allowing you to pick up the chest at the end. This method is very tedious, but effective.