Dragons are highly intelligent, usually highly magical (except for Pern dragons, which will be mentioned later), and disgustingly handsome reptilian species. There are as many kinds of dragons as an octravental heebiephone has keys, and each has its own particular pros and cons.
Pernese-style dragons, for instance, have no magical talent of any kind. However, they do have innate teleportational ability and highly developed telepathic skills, which gives them an edge when dealing with humans, or when quick transportation is necessary.
The firelizards one may see around TIM are smaller versions of these Pernese dragons, and it is rumored, their evolutionary predecessors.
There are too many other types of dragons to cover, with too many variations. If you want to know a dragon's abilities or whatnot, it's suggested that you ask him/her/it. However, do NOT offend the dragon, otherwise you may come to a very messy end very quickly.
The old pro verb is best: Do not meddle in the affairs of dragons, for you are crunchy and will go well with ketchup.
If treated properly, though, a dragon can be a valuable friend.