Nebula Dragons are nocturnal creatures. With the best eyesight to be found, they are often seen staring into space. Each dragon tends to observe a particular nebula and will eventually change their colors and patterns to match it. As the nebula changes over time, the dragon changes with it. The more intricate the design of the nebula, the better chance an individual has of attracting a mate. It is said that the markings on no two Nebula Dragons will be exactly the same.

Dragons are highly-intelligent reptilian creatures that—from a human perspective, at least—appear to live forever. Many different varieties of dragon exist, each with their own unique qualities, habitats, and behavior. Adolescence in dragons is usually marked by the growth of a hatchling’s wings, although not all breeds of dragons grow wings and some breeds have other traits that indicate the beginning of maturation. In Galsreim, dragons and humans coexist peacefully.

Yonaka hatched at night when the stars brightly twinkled above her head. The first dragon she met was Chunji Hua, a male Seasonal Spring Dragon, who hatched the same day. Since Yonaka is extremely active during a starry night, both Chunji and Yonaka are often seen together. She is like Chunji a calm dragon and likes to rest under a tree to just enjoy the silence. Although she sometimes is playful and helps Chunji with his gardening. Yonaka slowly fell in love with him. As a nebular dragon she often looks up to the sky searching for a matching nebular. Because her lover likes roses the most, Yonaka decided to match her wings with the Rosette nebula.

Yonaka has no fighting spirit, so she doesn't protect the group. Because she hatched in the middle of the night, she was given a Japanese name that means "midnight".