Danny is the son of Mr Freeze
So! Danny was adopted as a Kid.
It was never really that big of a thing to him, just a small footnote in his life. He never really cared about finding his Bio Family, or even looking into it at all. His new Family was enough for him, no need to complicate it all that much.
But then, the Accident happened.
After he got shocked by the Portal and passed out, his parents had rushed him to the hospital. Apparently his Heart had been pulsing irregularly, so they had decided to not take any chances.
While at the Hospital, the Doctors noticed a particularly strange result in his blood tests. So, a few months after he had been discharged (it took a while for the blood work to come back), they asked him to come back in for further testing.
At first, Danny was scared that they had found out about his Powers. But when he walked into the Room, they had other news.
He had been diagnosed with Huntingtons Disease, a rare neurological condition that apparently had no known cure. The only possible way to contract the Disease was to have inherited it from one of his parents.
They said it was in its early stages at the moment, but as time passed he would become weaker and weaker, and he would become more sickly. They diagnosed that he had just over 5 years left before he died, and there were no treatments or cures that could save him.
Danny got a second opinion with Frostbite, since he knew more about Ghost Biology and might know if it was truly a fatal Disease for a Halfa.
And yeah, it was. No matter how much of him is Ghostly, he is still half Human, and the Human Disease in his body can and will kill him. And there's no guarantee that he will become a full Ghost upon death. For all he knows it will just End him.
So, Danny had a time limit to find a way to cure himself. He didn't have much time to study, what with the constant Ghost Attacks, his School Work, and keeping his parents from attacking innocent Ghosts, but he managed where he could.
Speaking of his parents, they had been looking into the disease as well. But they seemed convinced that they could find a way to save him by simply dissecting a Ghost to study its biology. (It was as if this was just a convenient excuse to dive deeper into their obsession)
After a while, he mamaged to resolve the Ghost Attack stuff and got his grades under control, but he was still making little progress on finding a Cure.
So, he looked into other people who might be studying the same Disease, to see if he could look I to their research. But that search came up empty.
There was nobody who wanted to fund research into such a rare disease, so nobody was studying it. There was one man who was studying it, but he was a convicted Supervillain. Danny decided that he would be his backup plan, since he wasn't sure how Jazz would react if he teamed up with a known Villain.
He just kept on studying his condition.
It had been about 4 years since his initial diagnosis, and Danny was 18. And he needed help.
He had made no progress in developing a Cure, and his condition had worsened. He could barely walk without a limp anymore, and his limbs felt weaker by the day.
He did manage to get some luck when he found out that lowering his Body Temperature would slow the progress of the Disease. He was never more thankful for his Ice Powers than on the day he figured that out.
But he had hit a roadblock. He needed help, and unfortunately there was only one place he could go to get it. The Supervillain he had read about all that time ago, Mr Freeze.
Now he was headed to Gotham City to seek his help, even if it meant becoming a Villlain himself.
