There is a reason these dragons are called monstrous; they are gigantic, with a snake-like neck and tail. They are regarded as the most aggressive and powerful dragons in the world. Monstrous Nightmares are covered in red scales and spikes and have such a large mouth they can eat a Viking whole. They spit sticky lava that will attach to objects.
These blue dragons are covered in yellow spikes that can inject venom into an enemy. They have the hottest fire breath of any dragon; it can melt steel or turn a man to ash in seconds. Deadly Nadders are quick and agile, and they travel in groups.
These fat, stumpy, small-winged dragons are the laziest of all dragons. They spend the majority of their time sleeping, and even sleep while flying, only waking when they crash into mountains. They fly like helicopters, with the ability to easily move backwards and sideways and hover. They can't simply breathe fire; instead they must eat a rock, melt it in their stomach and spit it out as lava.
The most distinct species of dragon is the Zippleback. These creatures have two heads, both with their own personalities and thoughts. To make fire, one head exhales flammable gas and the other ignites it. Their wings are very small, so they spend most of their time on the ground.
The size of small cats, Terrible Terrors are more likely to be found under a Viking's floorboards than flying through the sky. Unlike other dragons, they present almost no threat to a Viking. However, when working together they are dangerous, and some flocks are over 200 strong. Terrible Terrors make a hissing sound before they breathe fire.