Luxembourg

Luxembourg is a very small country in western Europe, but I think it would also make a pretty good name for an ocean-dwelling supervillain from the DC Comics universe (as in: "Cower before Luxembourg, Lord of the Sea!"). Actually, Luxembourg is basically the exact opposite of what I just described, being completely landlocked and not at all accustomed to having things cower before it. Along with Belgium and the Netherlands, Luxembourg is a member of Benelux, which sounds like a medication whose commercials depict people kayaking and skipping through fields and such, but is actually a trade union/support group for the countries that are traditionally conquered first whenever there's a European land war. The head of state is a dude named Henri Albert Gabriel Félix Marie Guillaume. He's a Grand Duke, which sounds impressive but really isn't that tough of a job (although that might just be sour grapes on my part).

The capital city, also called Luxembourg, is similarly lacking in aquatic superpowers.