That's where his story gets abandoned, as the crisis on infinite earths never revisited him. But I see so much potential in Ultraa. He's a superhero who hates other superheroes, he grew up on earth-prime (our real world earth) and he seemed reluctant to leave in his debut story, etc. Ultraa could be the perfect antihero for the DC universe. His origin is very much like Superman, but they took some sharp divergences along the way. And you end up with this mostly peaceful alien raised in the outback, who just really hates the devastation he sees superheroes and supervillians bring to the world. I could literally read a comic all about him.