that freaky horn on the cover of chapter 289 signifies this is coming. this is the way he will be capable of doing battle with the upper level espadas and other extremely strong adversaries not to mention provide a way for him to surpass shinji as leader of the vizards, and thereby break off from his traditional/boring allies. he needs to be more rebelliious and get the whole "struggle against my evil internal self" dynamic back and this is how.