Board Thread:Fan-made Monsters/@comment-26517142-20190530202320/@comment-27950421-20190614125354

It's a more formal version of -san. -san is essentially Japanese Mr/Mrs. So for example Rep-san is the equivalent of Mr. Rep. -sama is more formal and used for people who are higher ranking, earned a great deal of respect, or are extremely attractive.

I imagine the equivalent to Rep-sama would be Lord Rep or something along those lines.