A Nightwalker are powerful, X-Class Yokai, that appear as enormous, shadow-like beings, that are capable of draining the life an individual just by touching them.
Nightwalkers are often large, and can occasionally appear to be shapeless masses of pure dark, but some will take more standard shapes.
The appearance of a Nightwalker can vary radically, as its body is composed of pure darkness. Most Nightwalkers will take a humanoid form, but they are capable of shapeshifting if necessary.
Nightwalkers are highly intelligent, and are considered to be strategists that know no rivals. They know how to make the best of their abilities, and even young ones are capable of harnessing their powers to the greatest extent. As their name would imply, Nightwalkers due to their best during the night, and during this time, they are all but unstoppable. However, during the day, is when Nightwalkers are at their most vulnerable, and it is then that they will be attacked.
The personality of a given Nightwalker is rather ambiguous, as they rarely interact with others, and the few who have met them, normally meet their hand at their hands. From the even fewer that survived a Nightwalker experience, the ones they encountered were calm, and passive, simply reaching for them, and never speaking.
As X-Class monsters, Nightwalkers are incredibly powerful. Since they are made out of pure darkness, they are capable of shape-shifting, and will sometimes disguise themselves as a way of achieving their given goals.
A Nightwalker is best known for its ability to drain the life of a human, or a Yokai, simply by making physical contact with them. In an instant, the target would be reduced to nothing more than a corpse. Why Nightwalkers do this is unknown, but is implied that they do it for sustenance. In addition, the mere presence of a Nightwalker, on its own, is enough to paralyze someone in fear.
Aside from their metaphysical abilities, Nightwalkers are also incredibly strong physically, capable of crushing rocks by simply picking them up. They are also able to run at high speeds.