Nightmare Serpent is a Supreme Boss in Magma Falls.
Encountering[]
The fight can be triggered from completing Bloodborne Sensei's quest, and purchasing the Crystal of Guilt at least once in the Empty Dragon Isle. Then, going to the last island in Magma Falls, the Vortex of Death Island, it will trigger the fight between the Nightmare Serpent and the player.
Battling[]
The Nightmare Serpent is not one, but two separate entities with two different hitboxes. One is named Sol and the other is Re.
WIP