Lastly, just call Batman

There is a reason why Batman is one of the most beloved superheroes – he is capable of doing wondrous feats, even if he has no special ability and is just a simple human being.

As seen in Justice League: Doom (or the JLA: Tower of Babel storyline), Batman can defeat the entire Justice League on his own. He is a master strategist – so if one wants Superman killed, all one needs to do is call on Batman. The Dark Knight would figure out a way of bringing down Superman.

And Batman, for example, will use a green arrow – as in allying with Green Arrow, who will shoot a green-kryptonite arrow into Superman (as seen in The Dark Knight Returns).