Is that the anime or the manga of Mermaid Melody? Because I've heard they're rather different and I'd like to check out whichever one has the darker elements.

Well now I'm even more confused about Precure, because I was looking at Youtube stats on Cure-related vids, and the top two demographics that liked those vids were invariably Female 13-17 and Male 30s-40s. So even if it's being marketed at girls, there are still lots of adult guys watching it. idk.

Regarding the deaths in PMMM, personally I draw a distinction between a character dying and then getting un-dead-ed, versus a character dying permanently in one timeline but surviving in another timeline. It's like what Umineko or Higurashi does — one of the Mamis may have survived and gotten a happy ending, but that doesn't help the other five or so Mamis who still got crappy endings. And then those five unhappy Mamis will fuse together into one nihlistic super-villain who will go hijack another canon and insert her own Mary-Sue character into it and then she'll end up dating the evil conglomeration of all the unhappy Sayakas and /end Umineko joke