Dark lord steel
One Thousand Club
One of my OCs is basically related to a famous wizard terrorist, and I like to think she's done fairly well. I find it interesting how different people react to her in the story, and how this helps shape her character and the conflict this causes with her family. It also creates interesting dilemmas in the story and it leaves a lot of room for character growth with both people. In some cases they've convinced her that her parents are wrong and she betrays them (although that doesn't always go to plan), in other ones she convinces the other character she's right and they slowly turn darker. There was even one where the two main characters ran away together and she had to kill her father to stop him from hunting them down. So I think Canon related characters can work, as long as they aren't just knock offs of the original Canon characters, or done in a really stupid way, like: I'm the eighteenth cousin of the great warrior from three hundred years ago so I'm super awesome at everything.*cough* Rey from Star Wars described perfectly well in the bold *cough*
I honestly hate the 'forced connection to a canon' type for one. Like for example if we're doing a fandom RP and you want to include OCs, that's fine and all so long as the canons get their spotlight..but when you make it out like 'Oh I'm Edward Elric's long lost cousin's uncle'. It's a hard pass for me.
I've yet to ever see that type of OC done well where they're related to a canon. It ALWAYS is a disaster from my experience.
Another one I hate is the 'edgy tragic backstory just for edginess sake'. We get it, you're angsty...but making a character mopey and traumatized just for the sake of it has always been annoying to me. Tragic backstories are sooo overdone imo.
Granted I've just lately got up the courage to forge my own OCs and feel like they're my own and not just knockoffs of some canon I like. Constantly comparing my OCs to canons and thinking I'm ripping them off was preventing me from flourishing as an RPer I feel.