The Dementor Lord of Azkaban is over a thousand years old, relatively young for one of its kind. Its existence has not been solely in the wizarding prison, having come into existence a few hundred years before it was built. It had wandered the lands long before deciding to settle and create a hive there.
It was not a bad existence for sure, with countless wizards to feed and learn from. Others of its kind often stopped by for a feed and told of outside happenings. No, not a bad existence, but when something different happened it was decidedly pleased. Or as pleased as a Dementor Lord can be.
A new prisoner, a female, felt strange. It was almost as though there were two of her, but that couldn't be right. The Dementor Lord was curious.
Eventually it learned the female was pregnant, a state of breeding for the humans. The Dementor Lord was curious. A tiny life developing inside! the female. I didn't really think, it didn't really feel much, and it rarely did more than sleep, but . . . The Dementor Lord was curious.
And then the thing, the baby, was born amid blood, pain, and tears. The Dementor Lord held the wailing infant up to get a good sense of it. It was tiny and its feeble mind screamed of discomfort, of cold and hunger, but there was something else. Something different yet familiar. This strange, newly made thing looked up at the being holding it and spoke, mind-to-mind, as the Dementor Lords do. It asked a question.
Daddy?
The Dementor Lord, now dubbed 'Daddy', decided to keep it. It was, after all, very curious.