Summary: As a result of a meddlesome God, J'onn goes into Martian Heat. As luck would have it, the only one around at the time...is Batman. JxB
H'ronmeer looked down upon earth, a frown marring his face. It was a confusing planet to be sure, with even more perplexing creatures living on it. Young and fragile, easily susceptible to invasion and destruction. And had in fact come close to death several times.
No doubt about it; were it not for those called 'The Justice League', the planet would have long ago died out. It was that same league that had caught his attention. More importantly, a Martian.
The last Martian of Mars.
That in itself was disturbing. The martians had been such a fine race of creatures. Well, the green ones that is.
Strong, wise, advanced and not that bad looking either. Not blood thirsty or cruel; kind and accepting. And they were all dead. All gone. Except for one.
J'onn J'onzz was completely alone. And he seemed content to stay that way it seemed, as the years passed without him finding another mate. H'ronmeer understood that he needed time to get over the death of his family and his race as a whole. So for a while, he was content to wait for the martian to heal.
However, as another year passed, and he saw the alien alone yet again, H'ronmeer got tired of letting it rest in the Martian's hands. If the Martian wasn't willing to make a move of his own, well then he'd make it for him.
The bloodline of Mars had to be continued.