Underbite

Underbite is a colossal Sea King built like a rounded eel, its back ridged with rows of spines. The defining trait is the heavy underbite, framed by a tusk at each corner of the mouth. Yellow skin scattered with brown spotting covers the upper body, while an orange dorsal fin crowns its form.

In common with the other Sea Kings, Underbite reveres Shirahoshi as Poseidon, its sovereign, and comes whenever she calls. It holds the vessel Noah in high regard, stepping in to stop Luffy from wrecking it because the ship is meant for a future purpose still to come.

Ranking among the ocean's largest and mightiest creatures, Underbite can clamp its jaws around sizable ships and crush them outright. It also shows clear intelligence, holding spoken conversations with both its own kind and Shirahoshi. A decade before the main events, the six year old princess unwittingly summoned it to Fish-Man Island during an emotional outburst when Saint Mjosgard menaced her mother, and Underbite surfaced to bite the noble's wrecked vessel in two before departing. Later it was again drawn out unconsciously by Shirahoshi as Luffy tried to destroy Noah, joining Mottled, Birdy, Googly-Eyed, Scales, and Topknot to seize the ship's chains and arrest its fall. The beasts spoke with their queen, marveled that Luffy seemed to hear their voices much as Roger once had, towed Noah toward the Sea Forest, and swam off.