Deep Sea Dragons, as their name suggests, spend most of their time in the darkest depths of the sea. They have a bioluminescent dorsal spine that serves to attract prey and communicate with their own kind. As with many deep sea animals, they generally eat whatever they can manage to bait. They rarely leave the ocean floor, surfacing only during breeding season. When they do choose to travel to the shallower depths, they avoid bright lights and will only come up far away from shore.

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.

Quartuor (meaning four in Latin) is Moonburst's fourth Deep Sea Dragon. He is the second born child to Primoris and Duas as well as their first son.  

Quartuor has a very serious personality, almost the exact opposite of his younger brother Quintcus. He shows no fear in the face of danger and takes great pride in his strength. He would be a great leader if only he could let go of his prejudice against those who are weaker than he. He shows great disgust toward dragons that breed outside their own species (most notably toward his sister, Tria who took Piano Powell, a Skywing dragon as a mate).

Quartuor is not the friendliest dragon one will ever meet. In fact it is best not to get in his way at all when he wants something.

His mate is Octoni. He won her affections by winning a battle against another male suitor, Senio.