Nightmarens come in different levels which indicate their overall strength level. The Nightmaren leader is Wizeman the Wicked, god and creator of the lesser levels.
First-level Nightmarens[]
First-level Nightmarens are the strongest and most intelligent soldiers, purposely designed by Wizeman to be his right hand men. They possess superior strength, flight and the ability to paraloop. They are given persona masks as a symbol of their loyalty to Wizeman, something that Reala adheres to in NiGHTS: Journey of Dreams, but NiGHTS abandons as a sign of their rebellion. Jackle was intended to be a First-level alongside Reala and NiGHTS but Wizeman mentions something going wrong, showing First-levels are difficult for him to create. Notably they have wills of their own, independant from Wizeman which allows NiGHTS to rebel.
Second-level Nightmarens[]
Second-level Nightmarens are less powerful than First-levels, but are still considerably more powerful and intelligent than Third-level Nightmarens. Second-level Nightmarens are capable of creating worlds of their own. They were tasked with leading Third-levels into the Nightopias, and to attempt to subdue and retrieve NiGHTS for Wizeman. All Second-level Nightmarens have the ability to fly with the exception of Queen Bella.
Third-level Nightmarens[]
Third-level Nightmarens are less powerful and intelligent than Second-levels, but are more numerous and more violent. They're tasked with gathering Ideyas after invading a Nightopia. Third-levels come in many shapes and sizes.
When defeated, Third-level Nightmarens will turn into orbs that can be collected by NiGHTS. However, if these collide with a Nightopian, they will lay an egg which hatches into a bizarre cross-breed species known as a Mepian which will contain both Nightopian and body parts of the Nightmaren the orb came from.
NiGHTS and Reala also appear as 'playable characters' in Sonic & All-Stars Racing Transformed, in which they both transform themselves into the vehicles and let a Nightopian and Goodle(a Third-level Nightmaren) race them. This makes Goodle the only Nightmaren outside of NiGHTS and Reala to be playable in any game.
Puffy, Gillwing and Wizeman the Wicked also make trackside appearances on each lap of Dream Valley in Sonic & All-Stars Racing Transformed. Third-level Nightmarens included are Shleeps and Kircles. A Hollow appears as a painting in the Puffy mansion section as well.
NiGHTS, Reala, Wizeman, Puffy, Jackle, Gulp, Gillwing, Clawz, Kircles and Shleeps also appear in Sonic Pinball Party on the NiGHTS table.
