Oshi no Ko

[Kraco]

weak idea: Ai's lover (father to Ruby and Aqua) is related to Sarina.
Why, just a hunch, for some reason Sarina felt like she had a complexion of a blond haired girl.
That could explain why Ai ended up in that clinic, Ai learned of the place/area from the father or connexions.
Related to Sarina: familly ? not mandatory, just a circle of friends or acquaintances but from the same origins is enough.
Again, just a weak idea.

Yeah, at the end of the day, those two were quite random people. They were Ai's fans, but that's about it. Doc's death was related to Ai, but Sarina passed away earlier due to her illness. Of course if the villain in the shadows was Sarina's father, and thus a much older man, perhaps in some twisted manner the man might have had something against Ai, because Sarina was such a big fan. But yeah, I don't really see it. It could be something more complicated, but for the time being I expect it to be just some media mogul, who couldn't resist having sex with a rising idol, but later started to fear for his own reputation. The kind of man who would have attented Epstein's parties.

[DarthEnderX]

Yeah, at the end of the day, those two were quite random people. They were Ai's fans, but that's about it. Doc's death was related to Ai, but Sarina passed away earlier due to her illness.

The other thing they have in common is the proximity of their deaths to wear the twins were born. It was all in/around the same hospital.