Far and away one of the most enigmatic of dragon breeds, the Sinomorph is shrouded in near-complete mystery. While the exact conditions that herald its arrival are not certain, it is said to only appear when called upon by all six Zyumorphs. Record of its existence may be limited to folklore and ancient legends, but recent sightings seem to suggest this storybook behemoth may truly walk the lands of Valkemare. If the stories of the past are to be trusted, its appearance serves as a beacon of light in the face of looming calamity.

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.

Zero Heat was the fifth member to join the "Zero Group", a group of Sinomorphs founded and led by Zero Sinaasappel, dedicated to letting Zero bad things happen to the dragons in their realm.

He is very protective and swift to anger, and nothing angers him more than seeing injustice done. In fact, he seems to have a special sense for cruelty, for even if he's asleep or far out of earshot, the colourful stripes on his body will begin to glow whenever someone in his realm calls out for help. He'll then leap up as if stung or hit by lightning, and dash through the air to save whoever needs saving. Those watching him streak past sometimes wonder how he can fly that fast without burning up like a meteor (he's actually twice been mistaken for one).