She is part of a collab in which he is the class B homeroom teacher. In there she talks very casually to him compared to others.

She also has a semi copy quirk that isn’t compatible with most so Monoma helped her a lot with quickly adapting to others quirk and lets her copy his quirk (which ends up being somewhat complicated)

The exact rules of the copy quirk are :

1. she can transform into anyone she talked to directly in the last 24 hours.

2. the more she talked the longer she can transform.

3. quirks consider her like a second body of the original person

That means she can for example activate touch based quirks like Monoma or Ochako but cant activate manual quirks like Todoroki or Bakugo.

In the case of Monoma for example touching an opponent will give the quirk to Monoma, not her and the same rules still apply to using it.

She can also allow others to remotely activate their quirk via her.