Nixie/nokks are aquatic creatures with upper bodies which resemble humans but instead of legs they have the tails of fish. They usually live in freshwater. Both Nixies and Nokks can shapeshift their lower halves between legs and a tail without the help of a medallion - however, they do still need one to appear human
Both nokks and nixies resemble merfolk with long fish-like tails, gills, fins, finned ears, sharp teeth and skin covered in blue-green scales. Nokks and nixies differ slightly in appearance. Nixies have gills on their necks and fins which resemble a dolphin's flukes edged in green. Nokks have spiny tail fins and matching ones on their forearms. They also have gills on the sides of their stomachs.
The Nixie is a mermaid-shaped water sprite with some inherent magical abilities; an uncommon trait among European creatures who usually lack magical powers. Their powers include mild shape-shifting in the leg/tail area, and the ability to control water to a certain extent. Their eyes are built to see underwater, so they must wear glasses when on dry land. They can also shapeshift 'away' their gills when not in use.
The bestiary alphabet entry reads:
"A germanic nymph-like creature, the Nixie is a generally friendly and beautify water-sprite who's primary concern is gossiping and shopping. They have the ability to turn into humans, but the hem of their clothing is always damp and they leave a trail of water wherever they go. A male nixie is called a nokk and isn't nearly as friendly as their female counterparts." It unclear if Skin Deep Nixie's have all of the features mentioned.
Nixies and Nokks can transform others, allowing them to become an aquatic creature. First seen here this transformation is temporary, only lasting as long as they stay in water/remain wet. This transformation is achieved though the use of Nixe/nokk essence (saliva), which can become addictive if abused. This transformation is better explored in the short story 'Nixie Spit'.
Nixe essence is sold in the Liverpool Avalon, and Jim has used it for practical jokes. Erin Dwight makes money selling his Nokk essence.
Nixies are available as a Medallion.
Example of Nixies:
The Nokk is the male form of a Nixie and have all of the same powers. Nixies and nokks are sexually dimorphic but are the same species. According to Madam U, they turn into flesh-eating beasts and lose their sanity, Kory has stated this happens when a Nokk is around 50 years old. Nokks, and presumably nixies, have an infinite lifespan, meaning that they can live forever. Because of this, some nokks prefer to remain unturned but they become a bit eccentric after 50 years.