Dragons are creatures with nearly unlimited life spans. They can survive for long periods of time, and no one has found a dragon that has died of old age. Adolescence 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. Once they hit adolescence, hatchlings change quickly, maturing to their full forms in only 2 years.

Dragons don’t communicate with each other verbally, but they will growl to scare off predators and frighten prey. Young dragons will emit an extremely high-pitched squeal when they are frightened. To communicate, they use telepathy with each other and to speak to other creatures.

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.

Sin came to Kaini's clan in a unique way. One night, when Kai was putting the last of the hatchlings to bed, a lone woman wandered into the cave. In her arms was a small, thin and sickly looking hatchling, its red eyes gazing up at Kaini questioningly. The lady explained what Kaini already knew; it was crippled because of neglect it suffered as an egg. Then the woman asked if Kai would care for it, give it a home.

Kaini of course agreed, determined to raise it lovingly to make up for its neglect. The lady gently placed the fragile dragon in Kaini's arms, and the second Kai had looked away, she was gone.

Introduced to its new home, the tiny hatchling quickly became close to Kai's other Neglected dragon, Lovingly. Even after Sinful grew up, the two dragons remained friends, and Kai often thought of them as brothers.