It’s Shinshia (I hope I’ve spelled it right) I haven’t gotten super far myself so I can’t translate the video myself, sorry. However, in the story so far, it’s suspected she may be of Shizu, given her skill. (Although, it’s also equally as probable that she got it from devouring one of the enhanced monsters, as it was shown that mirror monster, Izis, started feeding those creations to her and she gained skills from it) She is absolutely some derivative of Rimiru though, so calling her his daughter is completely fine. Great Sage scanned her and judged so. I wish Rimiru would stop being such an asshole to her, though. She’s not exactly asking for child support. She’s clearly got the mentality of a child, yet he’s constantly like “oh, I get it. You’re just a bitch trying to sucker me, right?” All casual tone. It’s so rude, she’s trying to figure out who she is herself, and he’s such an asshole, constantly chasing her off. (Granted, her first time of trying to prove she’s his daughter was rather violent, but she clearly knows no other way. He was kinder to every other monster, who only knew killing was the way. Why not her?)