For a chapter called naruto, it turned out to be a Gyoza episode 😜
but yeah, interesting backstory. A lonely, quiet child who decided to transform herself by adulthood. And then fate hit her like a truck and she decided to finally return to keep her grandma's spirit going. We only get small glimpses at her parent, but it seems like Renge didn't get anywhere near the attention she needed growing up (be it from society or malice, it's hard to say).
Also, small detail but it's interesting how Renge was contacted by the hospital. I'm not sure if that's just a cultural difference, but normally your next of kin are contacted first (or your spouse. But I assume Grandma outlived hers). Is the Mom okay?