Question (OC tagging)

Let's just say I have an original character (or a bunch of) but they're from a project (specifically, with existing title that i made) i'm working on. Is it allowed to include the title of the project (ex: "character_(name_of_media)" or "character_(artist_username)" ?

If that project is to get it's own copyright tag then it would normally be the qualifier for the character tags

They would use "character_(artist_name)". They would only use the project name if it was its own copyright tag, which would require a few things depending on what it was.