This breed of dragon results from eggs or hatchlings that have been neglected. They are usually rebellious, not obeying their masters, sometimes even attacking them. However, their neglect as a hatchling leaves them crippled, and they are weak compared to other breeds, causing them to stay with their masters for protection.

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.

Sinful Birthday is unsure about what makes him so sinful. Certainly, he's a neglected. Yes, he has a penchant for gluttonous chicken feasts and likes to take lazy full-day naps after such feasts. A bit of vanity, the result of comparing himself to less-beautiful neglected like Lady Dodger. A bit of envy of Lady Dodger for being universally respected. Some pride of his noble lineage. A burning lust for a marrow named Daleda who he can never have as a result of his neglected condition. Wrath for her mates. And a tendency to greedily hoard objects with her fragrance. Nothing sinful at all.