Let's back up in case you're not totally familiar with the story of the ring. Basically Lex Luthor had a piece of Kryptonite put in a ring he could wear and always have a weapon 'at hand' against Superman. The ring ended up in Batman's possession and Superman decided he wanted Batman to have it. If anything ever happened to Superman and he went out of control, the one person he knew could stop him was Batman. He felt Batman was the one person he could trust to keep the ring and not use it against him unless he had to. This just further showed the strength in their relationship.
As far as Superman is concerned, Bruce Wayne is dead. He was there when Darkseid blasted him with his omega beams and he brought his charred body back to the Batcave. Superman claimed that it was Bruce's body as he examined it down to its DNA.
If Bruce was dead, who gets to keep the Kryptonite Ring? We can assume that Dick Grayson has it since he became Batman. Superman has worked with Dick in the past. I'm sure he knows Dick can be trusted, especially if Bruce chose him to be his successor. But does that mean Superman would still trust Dick with his life? All it takes is one mess up for an enemy to stumble across the ring in Dick's possession and Superman is done for. How many times has someone like Deathstroke gotten the better of him?
My question is, if Bruce does in fact ever die for good, who would be Superman's number two choice to keep the ring. It can't be Lois since she's pretty much defenseless against Superman's enemies and I don't know if she could bring herself to use it against him if he was mind controlled. We've only really seen the deep friendship between Superman and Batman. I can't think of anyone that Superman would respect as much as he respects Bruce. Sure he's "pals" with Jimmy Olsen but come on, would you trust Jimmy with the ring? Maybe Wonder Woman?
Where is the ring right now? Does Dick carry it in a compartment in his utility belt? That's crazy too as we've seen Dick get beat. If someone beats Dick and takes his utility belt, they could stumble across the ring and do away with Superman. I'm surprised that crazy Jason Todd didn't try taking it when wandering around the Batcave right after Bruce's "death."
I hate to say that I don't have an answer to this right now. I'd have to really think about who Superman would trust as much as he trusts Bruce. Who do you think would be Superman's second choice?
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