The kaiju dragon is the strongest known dragon in all the vale. Witnesses swear they've seen a pack of kaiju dragons pulling entire mountain ranges in their wake, just as casually as you might pull a cart of robes. The larger mystery is what the kaiju dragons intend to do with an entire mountain range.
The Kaiju Dragon is a possible reference to Godzilla, as it strongly resembles the fictional character. The name "Kaiju" is also a Japanese term referring to a film genre of giant monsters or the monsters themselves, including Godzilla.