The last one is the Ultimate Dark Entity, also known as the Origin of Darkness.
It possesses unimaginable terrifying abilities, the power to change terrains, to move mountains and seas. Some are even the Progenitors of a group.
In addition to the Ultimate Dark Entity, beasts, wild beasts, and Hazard Spirits all have divisions of lower, middle, and upper ranks, which differentiate their strength.
The dark creatures Casio encountered can all be categorised within this system. For example, the Incorruptible Level, Immortal Level, and Indestructible Dead Blood correspond to beasts, wild beasts, and Hazard Spirits.
