Suggested by Anonymous Greninja is a pretty tough Pokemon to be sure. In his Ash form all of his abilities are greatly amplified and this is an issue for Phantom. Phantom’s speed is considerable but his attack power isn’t quite high enough to stop Greninja. They fight with similar styles but ultimately Greninja holds the edge in most stats and it’s hard to overcome such a deficit. Greninja will only continue to grow more powerful. Greninja wins.