>>58788391>PoMas confirmsNo it doesn't, it's licensed fanfic wank. Or else Ash in the anime would've mentioned the time he went training in Pasio and fought "a bunch of people who seemed like his old friends and rivals, but also weren't" during his road to the Masters Eight.
Also, Master SEX is a multiverse clusterfuck by design, it very explicitly pulls from different continuities so whether or not someone is the "canon protag" literally does not matter when it has no official bearing on the rest of the franchise.
If you raised the point that "Serena is the canon protagonist because according to GameFreak's prime timeline bible, she was the one who became Kalos Champion and caught Xerneas/Yveltal", then I would concede, but instead you went for the fanfic wank fruit.