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.

Quintcus (meaning Five in Latin) is Moonburst's fifth Deep Sea Dragon. He is the third born child to Primoris and Duas and is also their second son.

Quintcus has a fun and friendly nature. He gets along with most dragons and is accepting of others no matter who they are, where they're from, or what choices they make. When he found his older sister, Tria was still with Piano Powell, he agreed to keep their love a secret from the rest of their family because he cares for her happiness.

He is opposites with his brother Quartuor, although he too is very strong and courageous. His parents believe he would make a better leader than his brother, who's first in line for the crown, because of his caring nature. The problem is he often has trouble taking on and following responsibility. He must mature more if wants to become the next king.

His mate is Nonus. They met in the typical boy-meets-girl way, courtship followed, and they fell for each other. They plan to have a family.