A "recurring character" is a character that appears in multiple episodes or installments of a TV show, movie, book, or series. They are not the main character, but they come back periodically. Full definition
Each painting on panel presents a cast of recurring characters created to uncover these narratives, which according to the artist, center on metaphysical themes. (bermudezprojects.com)
I'm also partial to recurring characters from one novel to the next. (literarytitan.com)
The city mission contain all gameplay types and feature recurring characters. (playstationlifestyle.net)