Auto-translated
To start with, I would say the race should be of underwater creatures rather than water creatures—after all, so many different beings live in the world ocean, and mythical creatures are also present for the corresponding element. I assume that by "water creatures," mermaids, krakens, sea dragons, etc., are implied—everything material and quite plausible, not clones of elementals! As for penetrating the Castle—well—since we are talking about heroes, there might be no sea areas on ordinary maps—therefore, such a castle should be adapted for "life on land." It is assumed that the city will be protected from the outside by a magical barrier keeping the water inside the city—the main thing is that the fortress walls are on the outside and the battle is not fought underwater. The city surrenders after the garrison is defeated, and entering it can happen in some mythically inexplicable way—no need to rack your brain—these are heroes, after all, what else! :cool: