Nocturnal Heroes (also known as Nighttime Heroes) are the primary protagonists and supporting characters of the series. This term originated in "L'école des Pyjamasques".
A Nocturnal Hero are nighttime superheroes and vigilantes that come out in the night. Most often, they can be identified wearing costumes that are nighttime-themed, while a very few are exceptions. They also have a name that relates to the appearance of their costume.
The nocturnal heroes usually have magical powers (the activation of magic is treated more akin to super powers, an element that can be found in several anime that uses magic), while some of the heroes have standard superpowers, handheld weapons and martial arts that are beyond those of normal beings.
Some of the heroes are inspired from existing DC and Marvel superheroes, notably the characters from the PJ Masks who have some design elements based on the Marvel superheroes, as well as Energuman whose design is based on Batman's. While most of the heroes from Les Pyjamasques as a majority are inspired by fantastical and mythological elements, as well as nocturnal animals.