I really hate this trope of "introduce a character or element and then immediately make them/it plot-relevant" that stories fall on. It honestly ruins suspsension of disbelief. Especially this Johnny, who despite being an "important friend" to both Ky and Astra, has never once been even remotely hinted at until now. In EVERY flashback up until now, t's always just been "Ky and Astra". I vaguely recall Astra calling Ky his "one and only friend". That's not something I'm making up, right? Someone please confirm whether that's true. Suddenly introducing a character like Johnny who totally DID NOT EXIST UP UNTIL NOW and then immediately making them plot-relevant is just awful writing sense.
The only way to really justify this is if Ky and Astra are somehow having their memories modified or something...but even that would be coming out of pretty much nowhere.