She becomes the Poochie of the title. Dick becomes incredibly devoted to her for no good reason whatsoever, to the point that he tolerates her treating all of his other friends and family like total shit (including her THROWING A KNIFE AT BARBARA'S HEAD), and alienating them all in the process, and SHE kills HIS archenemy when HE isn't STRONG enough to do so, and THEN, she effectively becomes the PROTAGONIST of the title, driving all the action while he becomes some sort of adult-infant straight out of the worst hurt-comfort fics I've ever fucking read. How is she NOT a Mary Sue? The fact that Dick stands by her, even when EVERYONE else hates her, and even after she commits the sort of acts that he would NEVER put up with from ANYONE else, PROVES that she is, because the only character whose love matters to Devin Tarantula is Dick's