The Nightmare Type are technically labeled as hermaphrodites (dual gendered), though due to their appearance they are most commonly referred to with feminine pronouns. They have reproductive systems based upon both NH-29 and earlier kinds of Mishhuvurthyar. Like Nekovalkyrja, if they so choose they can reproduce asexually. Such a pregnancy can be started spontaneously whenever the Nightmare wishes, and a Nightmare can birth any Mishhuvurthyar species it wants. Roughly a week after the pregnancy begins the Nightmare's body will require her to determine her offspring's physical features and personality traits – the developing egg is encoded with the relevant genetic information. It is possible to include an automated random or manual selection of traits from another person (such as a sexual partner) through external medical intervention. About two weeks after the pregnancy starts the Nightmare will eject the egg from her body. A couple days later the offspring will hatch and feed in order to quickly attain full physical maturity. Assuming sufficient food is available, all types of Mishhuvurthyar will reach adulthood in less than a week.

In order to release her eggs a Nightmare can utilize an egg-laying tentacle, or else she can choose to retract the bony carapace present around her pelvic region. The carapace is also generally retracted during the act of sexual intercourse.

Because of their Mishhuvurthyar genetics a Nightmare can effectively function within a male capacity – inseminating another Nightmare's eggs or the females of another species through use of the appropriate tentacles that are part of the Neo Mishhuvurthyar Mishhuvurthyar Tentacles.