I'm actually curious with this childhood "friend". She acts more like a bully than friend. It'll be interesting to see a strong female with a good head on her shoulders as real rival than a standard typical love interest. Well, if she does become love interest, I am interested on how the author will handle the turnaround. As long as it doesn't feel forced or have sudden cringey character change, then I'm fine with it.
From looking at the raw,
it seems that he met her when he first arrived? Then I'm not sure if she gave him the spirit beast she's riding or forcing him to exchange with her. The boy ended up with a beaten face and her crying though. I don't know what happened