The Abyss (Phantom Divine Beast) are mysterious mythical beasts that occasionally appear from the Ruins where the Drag-Rides were discovered, starting ten years before the beginning of the series. They are predatory by nature and indiscriminately attack humans and animals. They are several times stronger than Drag-Knights; it would take either three high-level Drag-Knights, seven mid-level Drag-Knights or ten low-level Drag-Knights using general purpose Drag-Rides to fend one off.
Humans can control them using a mysterious golden flute called a Horn.
The Abyss come in many different species.
Large winged-humanoids with high intelligence. They have sharp claws and can fire feather like light bullets from their wings.
Large trapezoidal jelly-like creatures whose bodies are acidic.
A Golem is an Abyss in the form of a giant metal soldier with half of its body covered in rock scales. They are known for their large frames and superhuman strength, but are generally slow with easily avoidable attacks. Despite this, they are powerful enough that a single blow from them is impossible to defend against without receiving a fatal wound. These aspects, combined with their hard and sturdy metal bodies, make the Golem an Abyss that is nearly impossible to subjugate by normal means.
It is fortunate, however, that Golems are not an active type of Abyss, so if one does not approach carelessly, there will be a very small risk of being attacked.
A Diabolos is an Abyss with the appearance of a demon. They are generally taller than a large bear standing on its hind legs, have reddish-brown skin, and possess large jet-black wings. They have dagger-like fangs that are constantly revealed in their dark red mouths, and leak out purple smog as they breathe.
Diabolos are brutal Abyss, strong enough to single-handedly destroy a small town. They are Abyss capable of flight, and are generally several times stronger than their weaker cousins, the Gargoyles. They are able to breath fire and upon death, their bodies will self-destruct.
Because they rarely appear, there are no known written records of the Diabolos.
Seven Abyss with extraordinary power, one can be found in each of the world's seven Ruins.