I can recall reading an article years ago which claimed that some languages have unused "royal" pronouns. That is, these pronouns were only used to refer to royalty as a show of respect or reverence, however, such pronouns had apparently fallen out of favor over time with the general decline of monarchies in the world. I can't remember which languages the article claimed had these pronouns nor what the pronouns were.
I am aware of the concept of the royal we, which appears in English as well as a few other languages, however, I would consider this to be a case of an already existing pronoun being repurposed. I want to know if some languages have a pronoun which is only ever used to refer to royalty and has no purpose otherwise. Most likely, if such pronouns exist, I would expect them to be uncommon and modern native speakers might not even know them. It's also possible that I'm mistaken and pronouns like this don't exist in any major language, in this case it would at least be nice to get some confirmation.