Magma para-elemental sharks, and also pirates.
This makes me imagine the synergy of shark-surfing lava-pirates.
Clearly, these pirates have magical shark-rider bridle & boots that allow them to stand and steer the sharks with one hand, and avoid the negative effects of heat & poison gas.
"Yarrr! Swim me closer! Aye wants to hit the land-lubbers with me cutlass!"
Since the sharks are elemental denizens of both fire and earth, they can clearly surf over regular land (not just liquid magma), and thereby assault caravans. One of the caravans they assaulted was bound for the Monastery of Four Winds, and now the Four Sky Ninja Masters are hiring adventurers to investigate.
This would be a neat setup for the Temple of Para-Elemental Evil.