Harry wanted a baby. After all, Barty always told him that the day Harry appeared in his cell as a baby was the happiest day of his life. Barty always said Harry should be given anything he wants. But, every day, he looked around the cell. Every day, there was no baby.
One day, he asked one of the saltier Dementors (named Salty) where babies come from. Salty gives him a very detailed answer. Or, at least he starts to. Artemis covers Harry's ears and gave Salty a dirty look. Salty simply leered at Artemis and went off to look at the latest issue of "Dark & Dirty," a magazine for Dark creatures who want to let off some steam after being evil (or at least menacing) all day. Dementors normally breed solely for the sake of reproduction. Salty is considered an outlier as he greatly enjoys the breeding process.
With Salty distracted, Harry asked Barty and Sirius where babies come from. Barty told him that little Wizards appear by magic, “just like you did,” he added, a loving expression on his face.
The two snuggled a bit before Harry asked where Muggle babies come from. Barty got a strange glint in his eye and said that Muggles aren't born- they simply congeal out of a gutter somewhere.
Sirius hexed Barty and told Harry the stork brings both magic and muggle babies to parents.
If it was a stork that brought him here, then the stork could just as easily take him back. Harry couldn’t let that happen.
He convinced an army of Dementors to station themselves on the roof, watching the skies for a stork. "Don't let the stork in unless it has a baby," Harry told them.
Salty had been pulled away from his porn by Artemis to help guard Azkaban’s rooftop from any visiting storks. He was lurking menacingly while sulking like Harry deprived of dessert when he noticed Barty flying out his cell window in his owl form.
Unbeknownst to the prisoners, all the Dementors know about Barty’s transformations and outside trips. They didn’t stand a chance. Salty had seen wiser men than those three knuckleheads fail miserably at keeping a secret from Artemis. But he digresses…
Salty seized the opportunity to follow Barty and see what the man REALLY got up to.
The Dursleys had a baby girl since the last time Barty dropped by to hex the Muggles. He’s not able to avenge his Little Prince as often as he’d like. As a result, he’s not really up on the goings-on at Privet Drive. Of course, he could have asked Artemis, as the gossipy Dementor knows everything about everyone’s business, without ever having to leave Azkaban. Seriously, she could put Little Whinging’s nosiest housewives to shame! But I digress…
Barty ignored the baby girl in the playpen and went about his business hexing the other three Dursleys. However, unbeknownst to him, Salty followed him while he went on his little errand. You see, Salty was convinced that Barty was off getting his freak on. Salty was wrong, of course. Had Salty simply consulted Artemis for the latest gossip, he would know that Barty’s days out, like the rest of his current life, revolved around Harry- grocery runs, buying toys, and hexing Harry’s abusive relatives. While this may be interesting from a psychological point of view, it was deadly dull for the pervy Dementor. Salty was really regretting his decision to stalk Barty before the man was even halfway done with his errands. Seriously, it would save everyone a lot of trouble if they simply got the gossip from Artemis instead of running off on these harebrained schemes, but, again, I digress.
After Barty made his way back to Azkaban, Salty grabbed the baby girl and transported the screaming pink bundle to Barty’s cell. His duty as he sees it being done, he deposited the baby into the arms of a shocked Barty and glided off to read the latest issue of “Dark & Dirty.”
Barty wanted no part of caring for the “Filthy Muggle spawn,” the daughter of the people who tortured his Little Prince, but the Dementors refused to take her away. Artemis called it a character-building experience. She set up a shield around the child so Barty can’t harm her, or even set up a silencing charm.
Barty took care of the child’s basic needs but no more. He changed her diapers, but he didn’t sing to her like he did during Harry’s diaper changes. Sirius and Harry would make up for this by singing whenever Barty had to change the spawn’s diaper. Instead of giving her bubble baths with lots of toys and splashing like Harry got, Barty simply cast a cleaning charm on the baby and her clothes. He kept her in the same pink outfit, cleaning it every day. He fed her, but he didn’t care how much or little she wound up eating. He simply gave her a bottle to shut up the incessant screaming.
Harry, who had initially wanted a baby, quickly grew to resent the child’s constant screaming.
“Baaarrrtyyyy!” he called.
“Yes, My Lamb?” Barty asked, looking up from yet another one of the spawn’s diaper changes. “Did you want something?”
“Yes! I want the baby to be a princess, not a filthy Muggle spawn!”
“She’s a filthy Muggle spawn, not a Princess. Nobody can change that,” said Barty, putting the baby’s pink outfit back on.
“NOOOOOO! Barty, I want a Princess! She’s MY baby, and I want her to be a Princess!” Harry screamed, gearing up for a tantrum.
“Please, Lamby,” Barty started, but it was too late. The baby heard Harry’s yells and started crying again.
“She wouldn’t do that if she was a Princess,” Harry pointed out, seemingly forgetting the spectacular tantrums he had thrown during his year in Azkaban.
“Harry, m’Lord, I can’t turn a Muggle spawn into a Princess.”
“Yes, you can! I’m your Prince, and she’s my baby! You’re supposed to make her your Princess.”
“Anything you like, My Prince,” said Barty soothingly. “How do I make the spawn into a Princess?”
“Give her different clothes,” said Harry immediately. “I HATE pink!”
“What color, dearest?” Barty asked, hovering over the now quiet baby, who was watching the proceedings with bright interest. “Do you want her to wear green like you?”
“No, Barty! The baby has blue eyes! My green robes match my pretty eyes, so I look like your Prince. The baby should have blue robes that match her pretty eyes so she can be your Princess,” Harry replied, as if it were obvious.
Well. Accepting a Muggle spawn was one thing. Fulfilling one of his Little Prince’s desires was another. Soon, the baby was dressed in a magically transfigured pair of sky-blue robes.
“And you hafta sing to her, too,” said Harry.
“Yes, My Prince.”
“And give her snuggles.”
“Anything you say, dearest.”
“And teach her magic.”
“Lamby, Muggles can’t learn magic.”
“She’s not a Muggle! She’s my baby! That means she’s a Princess! And Princesses can do magic!”
Barty had never really joined the Death Eaters to torture Muggles. Sure, the Dark Lord’s approval and Him complimenting Barty on his skill with the Cruciatus was nice. But he was never aware enough of Muggles to have any personal grudge against them (aside from the three Dursleys, of course). His Lord despised Muggles, so Barty knew that Muggles were awful. If the Dark Lord despised the Chudley Cannons, he would have happily tormented the Chudley Cannons. If his Little Lord wanted a Muggle to do magic, Barty would do the impossible and teach her.
As Barty held his new Princess, Sirius slipped Harry a few chocolate bars, rewarding his fantastic acting performance and all-star manipulation.
Barty put his heart into trying to teach the baby (who, unbeknownst to him, was actually a Muggleborn Witch, not a Muggle- “How did you know that?!” Artemis asked Salty when she found out. “I didn’t even know that!”).
Despite an initial lack of success, the two bonded. The baby curled up on his chest and wanted to snuggle him all day, just like Harry used to. As much as he was proud of his Lamby for becoming an independent, powerful wizard, he missed the constant cuddles. She even had that baby scent Harry used to have. By the time the baby performed her first bout of accidental magic (turning Artemis' cloak pink, to Harry's howls of "I hate pink! Turn it back, Barty!"), the baby had Barty wrapped around her finger just as much as Harry did.