Childhood friends and playmates with Rin via their families, they've since drifted apart and Ruby has some abandonment issues about it.
Hangs out with Childe at rich people events; sometimes they pretend they're going to date just to get Ruby's parents off her back.
Neighbours with Felix in an old money part of town. She gets invited to dinner with his family and she thinks they hate her. One time in a game of truth or dare they made Ruby and Felix kiss to try and hook them up but Ruby is convinced they were just tormenting her.
Kim Dokja is one of her only actual friends and they've never met in person. They became friends on a forum as the only two people defending a particular webnovel and discovered they have similar tastes, so now they make recommendations to each other.
Followed Han Sooyoung around as a kid at social events until HSY escaped the obligations and they lost contact. Nowadays, HSY hounds Ruby to join her talent agency, partly to turn a profit and partly in an effort to take her under her wing because she suspects Ruby's family situation is Not Good.
Online friends with Yoo Joonghyuk via MMOs. Like with KDJ, has never met him in person and is convinced that their relationship would be ruined if they ever did.
Looked after Athy at social gatherings when Athy was younger and then started distancing herself as Athy got older for fear of [a long list of terrible things Ruby is able to come up with] so it's awkward now.
Was friends with Lumine for a time in early private school until Lumine had to move away, so now they're distanced and Ruby, unsurprisingly, has some abandonment issues about it.
Sometimes sings with Hibiki as piano accompanist, whether for exam purposes or performance. She's called on Hibiki when she gets enlisted to perform at upper class events so that Hibiki gets more exposure.
NOTES.