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.

Tanaka Seaheart is a kind and devoted mate to Kazuhiko Taiga. Her breed of dragon naturally inhabits the very deepest of deep water but when she was a hatchling and her kind are still around the surface often she fell in love with one of the older dragons. Kazuhiko was a thankfully a water type dragon or Tanaka might not have been able to bear it for she has a very deep love for the sea. Kazuhiko treated Tanaka with great respect and was ecstatic when even though she was an adult she frequently clung to the upper layers of the great underground lakes that connect to the sea in their cave looking for him. After many years of courtship they became mates. Though their mating wasn't blessed with an egg they have a Tanaka has a very energetic outlook for future little ones. Tanaka and Kazuhiko are often found in the caves lakes near the surface or the water, the only place they can ever be close to each other.