Glavenus

A Brute Wyvern that brandishes its heavy blue tail like a blade. The combustible metals contained inside increase in temperature with every swing, sharpening the tail and making it red-hot.

Overheated: The friction from repeated attacks raises the tail's temperature until it glows red-hot. In this state, the tail becomes sharper and drastically deadlier. Some swings even cause flames to erupt.

Fiery Throat: When its tail becomes dull, this monster uses its fangs to grind off the rust, which is stored in the flame sac in its throat to be heated and finally exhaled at extraordinary temperatures.