If we play by your own rules.
Bella:
- Encourages Jill to go on a date with MC, but fucks him behind her back
- Agrees to date him even though you're dating Jill. Hey MC, you'll talk to Jill about this, right? Yeah, okay then.
Sage:
- Teaches Jill about relationships and speaking up for herself.
- Helps her loose a bit with her easy going attitude.
There are no perfect characters in BaDIK and every girl is broken to some extent. But I can't imagine Sage being a bad friend to Jill. But Bella can, if she's with MC.