Fafnir

The ferocity and brute force of the northern dragons must be seen to be believed, but it is a dangerous prospect and one case were blind faith is safer. The fafnirae are powerful armored drakes that lair in caves and abandoned castles. They hunt along game trails or roads, springing forward to attack anything that crosses their path. The abundent spikes and scutes protect them from any attack, though their bellies are unarmored. The prudent dragon hunter will find a way to attack from below.

-Exerpted from Trismagistus, late 17th century