Wouldn't glowing energy blades be hard to cosplay with?The band was painted red, just like how Greninja's bridge above its nose was.
I didn't notice those at first but I can still see the blades as a cosplay feature. Serena turned Dedenne into a Spewpa so it is very possible that the blades are part of the costume.Not tomention it has some sick blades sitting on its back.
Besides if not Mega Greninja, I like the theory that this Greninja is special and was exposed to something and this Greninja is very special.
Edit: Yeah thinking about it, Ash's Greninja's differences seem too natural to be merely just applied cosmetic changes.