He is a gigantic green-and-blue tadpole-like creature attached to bat wings.
Gillwing is the boss of Claris Sinclair's Spring Valley dream. His arena takes place in a tree-like formation within a color-themed jungle realm in a deep space filled with stars. You could attack his head, but it will do very little damage. The quickest way to defeat this Nightmaren is to perform a paraloop right underneath the monster's body to kill him instantly.
- The star at the top of the Nightmaren tree-like formation in Gillwing's realm in NiGHTS into Dreams actually has use in Christmas NiGHTS into Dreams as after you defeat the "Christmas Gillwing" you are awarded the star that will eventually sit atop a very tree-trimmed Twin Seeds tower. This will win you the game in Christmas NiGHTS, but you do not recieve the star at the end of the battle in the original game.
- Gillwing's theme is called "The Dragon Gave a Loud Scream".