Whenever Riddler thought of his experiences in this little production, he wanted to shed bitter tears. Bruce had dragged Superman in and then washed his hands of him, expecting Superman to disappear for the long stretch of the main plot. All one could say was that the Joker Virus had truly fried the part of Batman's brain that was supposed to work.
Superman had lost his powers, not his memories. His personality had not changed. He was still Clark Kent. How could he possibly do nothing?
To keep Superman from interfering with the main plot, Riddler's assignment was to hold him back. In theory, Riddler should have had no problem dealing with a Superman weakened to the extreme. In practice, he had indeed held Superman back.
But the process had been torture.
Batman and Superman had their similarities, but what constantly caused clashes, confrontations, and conflict between them were the differences in both their personalities and beliefs.
As a human, Batman believed he was a supplement to humanity's legal system. Criminals whom the law could not punish, or could not fully punish, were his targets.
As a nonhuman, Superman believed he was another system within human society. That system was called Superman's justice. He judged whether something needed correcting according to his own values, and if it did, he acted.
Counterintuitively, Batman assumed the world had order and that he merely supplemented it, while Superman assumed the world was chaotic and that he was its savior.
That was why the two could never fully reach a consensus. Whenever such ideological conflicts arose, contradiction was inevitable.
In action, Batman focused on establishing a supplementary order, namely the deterrent power of the Dark Knight, to intimidate and punish supervillains who wished to exist outside the normal order. Superman himself was the order.