The Ocean Fangs

"Abandon ship! We've run aground boys. Take everything you can, you have time. From here we make a new one from her wreckage. Say your last goodbyes to the Super Sunshine Deluxe."
-Former Captain of The Super Sunshine Deluxe

Mountains Just Where You Didn't Need Them

Arguably the safest way into The Kings' Sea is from the north. It has none of the dangers posed by The Kraken's Maw, or The Dread Sea or The Ancient Sea. There's only one problem with entering from the north: an entire mountain range stands in the way. Thousands of rocky portrusions big and small peak over the waves, impeding any hopes that anybody could enter the sea easily. It's not as though you're terribly likely to die by navigating through The Ocean Fangs, but it's an arduous process that will likely leave you unequipped to deal with the dangers of The Kings' Sea.

Ship Shredders

Navigating the Fangs is hard. Really hard. So much so that a large ship that would ordinarily travel 70 or 90 miles in a day can travel at most 3 unless they want to suffer a horrible crash. They can't travel at night lest they bump into an unseen rock, and they need the assistance of smaller vessels to scout channels to see if they're viable. Smaller ships are slightly safer, but that means that entering into The Kings' Sea they're wholly unequipped to deal with its threats.
A crash here can be brutal, not only because it's incredibly easy to do, but because the rocks here seem like they're expressely designed with wrecking ships in mind. A hull can be ruined in a matter of seconds with ill placed rocks. And once you hit rocks and are stuck, you're bound to hit more trying to get out. It's a viscous loop that has sunk too many ships.

Smuggler's Haven

Because of their nature as densely packed mountains, The Ocean Fangs are the perfect hideout for smugglers and other folks who want to remain hidden or store hidden things. It's impossible to map every single channel and easy to hide things in one of the many naturally occuring caves. It's no surprise, then, that the mountains are crawling with them. Not all are aggressive or threatening, but there are enough among them that are that they are best left alone when found.