I never though of it like this One of my guys, a vampire Arnaud has an OC of a kind. It's a werewolf named Jean-Loup Garou (a no-brainer name lol).
Arnaud uses Garou as a persona who will talk to people when Arnaud doesn't want to, he usually closes his face by his palm when doing it ("talk to the hand" style). He also likes to imagine little funny stories about Garou's life or uses him when "asking for a friend" situations.
Arnaud also has a collection of commissioned art pieces with Garou (since 1787), that sometimes suffer from different disasters such as his places of living being burned down, art going rotten, or even being stolen.