I honestly thought when I read the raws that this was Hosshi's sister playing tag when she was younger or something. Oh well, one-off characters is fine too. Interesting to note is that these kids seem a few years older than Daiki's gang (in fact, that is part of why I thought it was Hosshi's sister, since they seem to be around her age) but seemed to be completely unaware that Kurona's ears and tail were out (which goes to imply that they couldn't see them - it would have been a bigger shock to some of the kids if they saw both girl and cat forms like how Hosshi's sister and her friends saw Kuma as either dog or girl.)
On other news, I did finally get my physical of volume 19. Loving it, if only because we actually get to see Shishimaru get pissed off for once.