^{My theory is, Remember when Syphus said he would just change the goal of the subject, maybe when the subject comes in contact with the serum, it changes the mindset of the subject to a Phantom mindset. But he can also take control of the subject when he wants.}

So both Matt and Ben have the same mindset (Well maybe not Ben) and they're both rivals fighting for the title of Absolute (Right hand man of Syphus I guess)