Actually Sera could have just wanted to show Conan her phone because it's same as Conans now, and Sera seems to like Shinichi/ConanPhantomWriter wrote:But that is also another theory that makes no sense. It seems off with both Jodie and Akai, if they were to have had a child, to have Sera take care of the kid. Yeah, they're working in a dangerous field and dealing with very dangerous people, but they seem like they'd come up with a different solution than have his younger sister take care of their child. And the timeline makes no sense. Sera is 17. Before Akai wormed into the Black Org, which was 5 years prior, Sera would be 12. It would be downright irresponsible to force your kid sister to raise your child and that's not either Jodie's or Akai's styles at all.
On top of that, why would Sera then be so cryptic, hiding them, but also showing Conan and hinting to him about said kid, if it were simply a normal relative, be it her brother's child or, more broadly with this topic, a cousin? [I'm using normal in relative terms, as the Akai family all seem to be incredibly sharp in ways most would consider abnormal.]
That would either be Sera deliberately going for a red herring for literally no discernible purpose or the kid is important in some way we can only guess about because we don't have much information. All we know for sure is the kid is a relative of the Akai family, Sera is in contact with them, and that they're important in some way, enough so that she thinks Conan ought to know about them.
And this is a series where there is a poison that can turn people into little kids physically.
also, remember, she said that she can't tell who she is until "the time comes"
and she's also saying that she's planning on moving elsewhere soon

