Why are they never really related!?
Well… can’t say I wasn’t expecting this. But ELEVEN episodes and you throw it at us during the final!? That’s more rage inducing that saying it in the first few, or midway, the run!!
Goddammit.
Open Your Mind
~Fly to Higher Mind Shelter~
Open Your Mind 
I was surprised to know the fact that they were not related by blood, so I know your feelings of damming, but such an epilogue would be continued to the next season, so animators made this ending, I think.
Anyway, this anime’s title is not appropriate, That is a lie where you can sometimes see some anime originated from right novels.
The animators made this ending? So this isn’t in the light novels?
No, animators didn’t deviate original story, but they made the final that Akito said to himself no blood relation with Akiko, which is one of cinematographies to sometimes imply the second series.