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.

Paper dragons are not truly living creatures. They are pieces of parchment enchanted by magic, and as such, are very vulnerable to fire. However, they behave almost like dragons. The only place where their behavior differs is breeding: paper dragons cannot breed.

Onimon is a fierce paper dragon. He is very light, and physically weak, but that doesn't make him completely weak. In what he lacks in power, Onimon makes up for magic and smarts. Since he is alive because of magic, Onimon knows a little magic. He cannot use too much or he will kill himself. Onimon is also known for actually strangling dragons that harm his family.