Nightmare Klonoa is the dark doppelganger of Klonoa in Klonoa: Dream Traveller of Noctis Sol. He captured Lolo in a dream world, posing as the real Klonoa to taunt her and lie to her that he (the real Klonoa) won't return for her. Nightmare Klonoa was then confronted by his real counterpart, and after a battle with them shooting their respective Wind Bullets at one another, Klonoa successfully inflated his evil alter ego, temporarily immobolizing him.
When the nightmare began to crumble around them, Klonoa and his friends were teleported out to safety by Lolo, leaving the inflated Nightmare Klonoa behind. He eventually became free from the effects of the Wind Bullet, and was dismayed that the heroes left without him. Nightmare Klonoa was then contacted by a mysterious voice, who offered to help him see Klonoa and his friends again.
- Nightmare Klonoa is never mentioned by name in the webcomic. His name was only known when it was confirmed by Jim Zub on Twitter in response to a fan.
- When asked if Nightmare Klonoa was inspired by a scrapped doppelgänger character from Door To Phantomile, Jim Zub stated that he didn't intend it himself, but that "Ariga may have been channeling that".