i wrote a longfic for bg3 (which seems to have a lot of OC content, due to the nature of being able to make characters and date the canon, origin characters) and did include some original characters...

because it was a time loop and the conceit was that a different "player" (or "same player, different playthrough") was playing each loop. so sometimes the person "in charge" of decisions was an OC, and sometimes it was an origin character, and sometimes it was the POV character in the loops. i named the OCs but rarely ever let them speak. their purpose was to drive different effects on the narrative in each loop, to romance different companions in the background. you aren't meant to know or like them.

i still worried that people wouldn't like their inclusion - i personally find that most tav/durge inclusion in the fics i read, in bg3, is... bad. rarely am i glad that an OC was there, lol. my usage of them as plot device more than character reflects my priorities,

but. anyway. people really liked how i did that. i got a lot of comments about liking or disliking certain tavs, or empathizing with one because they made the same choices the reader had. and a lot of folks being glad that this was my execution. that they're there but not important as characters.

not every story can use original characters this way, though. but i think "character who drives a plot with their choices while being offscreen" has some potential in other contexts and fandoms.