u/AgreedWolf38

As far as I know, Mega-Greninja is the third-fastest Pokémon belonging to Champions, tying with Dragapult.

I have my Greninja fully speed-trained, but when I Mega Evolve it and battle other Pokémon, they always outspeed me (e.g., Mega-Delphox, Mega-Pyroar, Mega-Raichu Y, and even a Weavile); none of them had a priority move or a Choice Scarf, nor were they boosted by Tailwind.

And I don't know why they attack first, before I do.