While Mitakeumi is having the tournament of his career, I thought I’d take a look at the kanji in his shikona. 海 is well known. It means sea or ocean and is commonly used in wrestler’s monikers, from Okinoumi to Kitanoumi. (It’s also my son’s name, though the reading when used alone, “Kai” is different.) At the other end of the spectrum, 嶽 is super rare even though all four of the radicals that make it up are very common.
御 sits somewhere in the middle. It’s not used often and actually seems to be falling out of favor. But you do see it. It’s not that it doesn’t have a meaning but it doesn’t have an easy direct translation into English. Basically, it’s an honorific and is often replaced by hiragana “o” or “go”. For example, I have seen it used in 御茶 (ocha) for tea and 御飯 (gohan) for rice but those are usually used with the hiragana. The menus at these fancy restaurants are often 御品書 (oshinagaki).
It’s also often used by job-seekers when they write to companies. Since it’s a formal setting, they often use 御中 after the name of the company or institution. When the company writes back, they address the person with -様. But likely it’s most well known usage is in the name of a Tokyo train station: 御茶ノ水.