Such an odd adoption made for some strange changes to the island.
First and foremost, since Godzilla (and all other kaiju for that matter) lacked the dexterity required to gently handle a human infant, Mothra's worshippers were now allowed to roam the island freely. Where before Godzilla regarded their presence outside of the grotto as a hostile incursion, he now grudgingly accepted it, and where he lead, most other kaiju followed. That said, Kamacuras and Kumonga's nature as predators outweighed any fear or respect they might have had for the monster king, and so their territories were still off limits to anyone who did not wish to die a swift but horrible death.
Jet Jaguar left, but came back a few hours later with what seemed to be an entire warehouse's worth of infant care supplies: books, diapers, baby formula, and more diapers. Only after unpacking everything and storing them where the elements could not ruin them did he set off once again for the UK. The robot still needed to resolve the problem that had taken him there in the first place, and after that he needed to begin collaborating with the authorities to search for the Death Eaters and the mysterious figure calling himself Albus Percival Wulfric Brian Dumbledore. Still, he would find the time to visit, but his typical distance would lead to Harry thinking of the robot as an uncle more than anything else.
It fell to the Shobijin to educate Harry, insofar as one can educate a baby. While the Infant Islanders did their part in his day to day care (after all, it is impossible for a pair of two-inch tall women to care for a baby many times their size) it was generally accepted that Harry's heritage meant that he would want to learn the English language. Since the twin priestesses were also Infant Island's diplomats, they had seen fit to learn to speak and read English as well, so they spoke and sang to the baby daily. Their audible presence but lack of visible presence would lead to Harry thinking of them as beloved aunts rather than mothers.
Godzilla came to regard Harry as a son due to a combination of circumstance and instinct. Minilla, though unable to interact physically with the infant, liked to watch him, and as a result Godzilla had to watch over both of them. Gradually, his paternal instincts began to extend from Minilla to encompass Harry as well.
How Harry came to regard Godzilla as a father requires a bit more explanation, but it too is a result of Minilla's fascination with the infant Harry. As a result of Mothra's blessing on the baby, the entire village of her worshippers took care of Harry in shifts, so while the human faces looking down at him always changed and varied, Harry could always see Godzilla looming somewhere overhead.
As Harry grew up the Shobijin and the Infant Islanders began to notice strange things happening around him. Things he wanted tended to fly toward him, and when he wanted to play hide-and-seek he often wound up in places it would be extremely difficult – sometimes impossible – for someone his age to get to.
But it was only conclusively accepted that something was different about Harry James Potter when he teleported in front of everyone.
One afternoon, a four year old Harry was running along the beach racing Minilla to a rock jutting out of the shallow water further down as Godzilla slept leaning against a natural arch in the rocky cliff face. It was difficult given Minilla's greater stride length, but young kaiju was always slow and uncoordinated (something that many suspected was a result of his premature hatching). But then Minilla tripped over a boulder hidden just beneath the waves. The prince of monsters had enough time to screech in panic at the sudden falling sensation, and Harry had just enough time to turn around, scream, and shut his eyes.
Godzilla ran up but was too late to stop Minilla from falling. No one else had any time to do anything, but suddenly Harry was gone just before Minilla's bulk landed on him… and Harry's screams were now coming from behind the horrified onlookers. Everyone turned around and there was Harry, eyes shut and shivering, with no footprints leading to where he was and no other signs of how he could possibly have gotten there without anyone seeing him.
Godzilla and Minilla made confused grunting sounds. Though glad that Harry was not crushed into paste, they were confused as to how he wasn't. The same could be said of the Infant Islanders. They were not afraid of Harry, they had known him for too long, but they did not know what to make of him. They prayed to their goddess for guidance.
The twin priestesses spoke to Mothra as well, and the caterpillar kaiju reminded them that it was the robot Jet Jaugar that had brought Harry to the island, and so perhaps the robot would also know the answers. She also reminded the Shobijin that Jet Jaguar had mentioned "oddities" in the letter he found with Harry, but had chosen not to elaborate at the time.
So when Jet Jaguar next arrived the twin fairies confronted the robot with these incidents, asking to see the letter for themselves. Without responding, the robot handed them a copy of the letter that he'd had made when he first presented it to the authorities. Moments later, the Shobijin chastised him for rejecting the possibility of magic. Not only did he live in a world of aliens, giant monsters, and fairy priestesses, his knowledge of kaiju should have included the prophecy predicting Mechagodzilla's attacks, and of the kaiju golem King Shisa.
As abashed as a robot could be, Jet Jaguar managed to relay his apologies, and then explained that as a robot – a thing of science and reason – such a thing as counterintuitive as magic was, well, counterintuitive. It would answer a few questions that his investigations had raised, but in turn it would raise many others.
Mothra entered the "conversation" and bade him to elaborate, and through sign language and his limited vocalizations, Jet Jaguar relayed a strange tale.
His first act (after dealing with the multi-year and continent spanning criminal empire that lead him to the UK in the first place) had been to fly to the local police station in Surrey, where he supplied an audio cassette of what he had heard that night, and the letter, original envelope included. The robot's fame and reputation for assisting law enforcement across the world aided him greatly in obtaining their cooperation and a copy of the letter for his own records. His aid in uncovering the criminals who'd led him to the UK in the first place also meant that the robot was certified as an honorary member of law enforcement in Britain, so he easily got permission to question Harry's aunt.
That was where the investigation turned strange. It took far, far too much prompting by Jet Jaguar to make Petunia Dursley admit that she had ever even had a sister, let alone that she knew her sister had a son. The woman made clear multiple times that she wanted nothing to do with such "freakishness" a word she used multiple times in describing her sister and "her kind."
That line of investigation having lead to a dead end, Jet Jaguar returned to the police station to find the next anomaly. When he returned, no one had any memory of him entering before, nor any memories of his cassette or letter, neither of which could be found. Having preserved the copy of the letter, but realizing that something sinister was afoot, Jet Jaguar simply left to continue his investigation alone.
Searching through libraries' archives was slow, but as a robot Jet Jaguar was patient. There were no mentions of Death Eaters anywhere, nor were there any mentions of Voldemort, but there were other, stranger clues he found.
In searching for the names "Hagrid," "Minerva McGonagall," and "Albus Percival Wulfric Brian Dumbledore," there was only one thing that all three had in common: records of them attending a private, but unnamed boarding school in Scotland.
Following a hunch, he looked into the records of James Potter, and Lily's maiden name, Lily Evans. They too, had gone to the same school. Sensing a pattern, Jet Jaguar began looking for mentions of this school. A difficult task for a human, but slightly easier for the algorithms that comprised the mind of the robot. Something his pattern recognition software was able to determine was that while this school was never named, the same words and phrases were always used to describe it.
It was a private boarding school, it was prestigious, very selective, and located somewhere in the Scottish Highlands.
Scanning multiple records for information he was also able to determine that this school began taking children in at the age of eleven. From there records on all such individuals were very sparse, only rarely providing grades. Most of the time these children simply… vanished. There were never any photos of them from the months of September to June until they had reached at least the age of seventeen and more commonly eighteen. Yet their families never reported any of them missing, even in cases where records provided no indication that they had ever returned.
Jet Jaguar had uncovered conspiracies before, but never one so large or seemingly pervasive. It was at this point that he realized how long it had been since he'd last seen Harry, began to fear for his safety, and decided to fly towards Monster Island once more. Then, after seeing his fleshy "nephew" the Shobijin confronted him, thus bringing the story full circle.