The Warrior of Sunlight covenant is one of the many covenants you can join in Dark Souls III, and it allows you to become a golden sunbro that enjoys engaging in jolly cooperation. To join the covenant, first you need the Warrior of Sunlight covenant item. After reaching the Undead Settlement, proceed through the level until you reach the large tree fire with the witch and surrounding mobs. Ignore the bridge to your right, and proceed straight.
You’ll find yourself in a dilapidated house with a hole in the middle of the ground. Drop through the hole. Instead of going forward to fight the red-eye enemy and the two caged foes, turn around and head up the stairs on the right. Look near the door to find another hole in the floor, obscured by some wooden crates that you can easily roll through. Drop through the hole and you should find yourself in a small room with a pot of Estus soup in the corner. Opposite the pot of soup is the covenant item that you seek.
Open your menu to equip the item, and you’ll officially be part of the Warrior of Sunlight covenant.
Be sure to check out our Dark Souls III wiki for more tips and tricks.