The door to the left of the Flying Thief's corpse cannot be opened. Pick up the purple item on the left to challenge the boss, the Remains of Master Blue Sea.
The boss fight against the Remains of Master Blue Sea is simple. Just deal with nearby enemies while breaking his shield; defeating the surrounding enemies also helps break the shield.
His red light attack is purely white, spraying golden light forward.
After defeating him, you can obtain the Shadow Armament "Kuyoji Prayer Beads".
