Aquaman (movie)/HP cross. Enjoy!
It was probably the second task that caused it. Or at least the moment she finally cracked the riddle of that blasted egg.
She didn't know how long she spent under that bath water, but it was long enough that she realized something was off. Up until this point she generally took showers, as there wasn't a proper bath in the Dursley house. And her so-called family never took her swimming in the summer.
This was the first time she went underwater properly.
Since there wasn't anyone around, she ducked under again. This time she wanted to see how long she could hold her breath.
It wasn't until the third repetition of that ridiculous riddle that she realized something.
She was breathing underwater.
Iris was completely confused by this point. How was she breathing underwater like it was air? She hadn't cast a spell or taken any potion.
Considering how long she had been in the bath, she decided to leave and investigate later. If she spent too long odds are that someone might come in and find out she was in here.
She wrapped up her egg and got dressed.
However she left with a bigger mystery than the minor one she came in with.
A few days later...
After discovering Dobby in the kitchens, the elf was more than happy to help Iris test out her newly discovered ability to breathe underwater and to find out if there were any other latent abilities she had that had been missed because she never spent much time underwater.
It wasn't just the breathing underwater. Iris was pleasantly surprised that she could control water and even create an air bubble around her. It would take some doing, but she was hoping to find a way to create a weapon made out of highly pressurized water in a confined area...sort of like a liquid knife or dagger. She knew high-pressure water could cut through steel, so that sort of thing would be very useful in areas where she couldn't use her wand.
Another interesting thing she discovered was that she could talk underwater too. Sort of like a mermaid, only she didn't shriek when in the air.
It was too bad she didn't have much time to experiment further in that fascinating room Dobby told her about. She would have used the docks, except she didn't want anyone knowing what she was doing and as far as she could tell the map didn't really list the room she used. Besides, that water was freezing this time of year.
Mermaids looked nothing like the portrait in the prefect's bathroom. They looked like fish-people and many had rough spears and the odd trident, but they didn't look like the portrait.
Iris didn't need to strain her hearing to notice the confusion in their voices. Sure, they had agreed to keep the surface-dwellers underwater, but they seemed to instinctively notice something different about Iris.
Rather than free Ron right away, she stuck around to make sure that the others were retrieved safely. Particularly the young girl who she suspected was related to Fleur.
Hermione and Cho were freed, but Fleur never came. Iris suspected the hour was well up, so she went to get the little girl first and then Ron.
"Only one hostage per human," said the merman.
Iris glared at him.
"No offense, but I'm not leaving an underage girl in this lake any longer than I have to. It's freezing and she's spent too long underwater already," said Iris flatly.
Iris couldn't accurately describe the shock on the faces of everyone in the area.
"A High Born! That bearded fool said nothing about taking the precious person of a High Born hostage!" said the merchief irate.
Now it was her turn to be confused.
"I have to bring these two back to the surface. But I will come back later to get a proper explanation," she said calmly.
Iris was rather happy the merchief lied about what she could do. Apparently the wizards were all under the assumption she ate the plant. But now that she had an idea of who to ask about her abilities, there was no way she was letting it go!
A week later...
The merchief was a mountain of information. Apparently Iris' abilities were somewhat common in "high borns" which was the term for pure blood "Atlanteans". The mermaids in the lake were a small colony that had moved away from the hustle and bustle of the "Fishermen" kingdom and were considered rather odd because they lived so close to the surface dwellers, which was what they called the air breathers.
The ability to manipulate water, both above and under the water, was a mark of someone from the Xebel bloodline. Mostly those connected to the royal family, but at least she had a lead. However the current king didn't particularly have a good opinion of people from the surface and he was close to King Orm, who hated them because his mother had fallen in love with one and had been sentenced to the Trench for loving a human.
Most of the information on Atlantis and Xebel was all highly out of date, but the merchief did have the bare minimum, mostly thanks to their cousins in the Fishermen kingdom who told them all the current rumors whenever someone from the colony visited them during family reunions.
She would likely find more information from the Fishermen kingdom, but visiting would be tricky because it was in the middle of the ocean and they didn't have any coordinates that surface dweller could use.
If it wasn't for this stupid tournament, she would have left Hogwarts and started looking for the Fishermen kingdom.
Unfortunately she couldn't just up and leave. Not until this mess was over.
However there was something she could do, and that was track down why the headmaster had lied to her about Petunia being her aunt. If her mother was a high born, as the merchief implied, then there was no way in hell Petunia was blood related to her. And that meant the 'blood wards' were complete bullshit.
It took a lot of long, boring searching in the library. But eventually she discovered a book to explain some of the things she had noticed that fit neatly with the merchief's description of "high borns".
Considering her luck, it was probably best that she not check this out openly.
Good thing there was a small bookstore in Hogsmeade. She had never been herself, but she knew Hermione would be a frequent customer if she had the coin for it. A lot of students happily sold off their Lockhart books the first chance they had after his memory loss.
Iris slipped out of the castle and headed for the store, her bag loaded with coins.
What little they had on the subject was limited, and the books were rather old. It cost her ten sickles for the lot of them.
They were fascinating. Apparently the wizards had come across others with similar abilities before and had a classification for them already.
Children of Nimue. Common signs of being a child of Nimue included the ability to breath water as easily as air, having the ability to see in darkness with no trouble and being unaffected by the water pressure in the depths.
From what she could tell, there hadn't been a legitimate Child of Nimue for two hundred years. Considering those who could come to the surface were all "noble pure bloods", it was likely they looked down on the surface dwellers for their inability to survive underwater and thus felt it beneath them to leave the water long enough to actually sleep with anyone.
Well, there was a chance there was one other person with her abilities, but the merchief wouldn't be able to tell her anything about where they might be since they only heard about rumors second hand long after they were more or less public knowledge. Besides, none of them were 'high borns', save for the merchief. And he was so low placed among the noble heirarchy that he wouldn't be able to make any waves even if he tried.
After the third task...
Iris gave her winnings to the twins, and asked them to keep an eye on Hedwig as she didn't want her owl to suffer through another summer with her 'family'. Besides, this meant that they could start an owl-order business and earn more capital over the summer. Hedwig certainly wouldn't complain about the extra exercise.
With that done, she waited until the train was well on it's way to London before she slipped out of the compartment to use the loo.
If anyone asked, the twins were going to tell the adults that she had spent the train ride with them after they goaded her into one last game of poker before she was stuck with her family for the summer and lost track of time.
Iris took her broom and carefully flew to London ahead of the train. It took her a moment to find a place to land and walk the rest of the way, but with her mundane apparel it was unlikely anyone would notice one more teenager on their own so long as she wasn't causing trouble.
It was incredibly liberating, being able to wander around muggle London without having to deal with the Dursleys or anyone trying to act as her minder.
Her first stop, once she reached the Leaky Cauldron, was to dump her trunk and anything magical like her cloak and photo album into her trust vault.
And wasn't that a nasty surprise, learning that the vault she had been using for years was merely a trust vault and that there were others. The goblins were less than pleased, as they had assumed she was an idiot for not dealing with her finances personally.
She told the goblins to audit all accounts under her name, starting with her trust vault and to take back any gold spent while after her parents death that couldn't be accounted for down to the last knut with as much interest as they could get away with. She didn't tolerate thieves, much less the people who had been profiting under her family's tragedy over the past thirteen years.
Her next stop, after leaving some darkly amused goblins, was to visit muggle London. As much as she wanted to keep her wand, the fact was that she could be tracked down if she used magic. Besides, she wanted to learn more about her newly discovered abilities and not have to think about magic for the summer.
Opening up a safety deposit box and an actual account was surprisingly easy and thankfully didn't require a guardian's consent. As far as the bank was concerned, she was just another teenager who wanted to put their money from whatever summer job they acquired into a proper bank account. They could care less what she stored in their deposit boxes so long as it wasn't illegal or dangerous.
Once they proved that the gold bullion she was depositing was not only real, but perfectly legal, the bank was more than happy to set up an account for the value of the gold. After all, the amount she brought in was enough to make her a very valued customer in the bank.
She got past the adult's suspicion (like why she didn't want her card sent to a post address) by claiming her uncle had a drinking habit and that she didn't wish to fund it. Oh, and the gold came from a stash her grandfather had left behind that she wanted to invest properly.
Since the gold didn't come up as stolen, and the girl was rather skinny for her age and had all the small signs of having a rough home life, no one was going to question it. Besides, it wasn't that unusual for an account to have a password or the like in order to access the funds. Even if meant having to go to a little extra effort to prove you were legally allowed to withdraw from the account.
Her next stop was getting a new outfit. Her current underthings were barely the right size and she wanted something a bit nicer t wear before she hit the store that sold underwater gear. Not that she would need scuba gear, but having things like an underwater camera would be nice to have for later.
In the end she settled for something close to a very modest two piece swimsuit to wear as her underthings once she started working around the water. The fact it could double as an actual outfit so long as she had a pair of sandals on was bonus, especially around the more pleasant climate like the Bahamas. Even if the bottom skirt was a bit shorter than she liked, and the top had straps instead of proper shoulders. A t-shirt would fix the worst of that though.
Once she acquired an underwater-friendly pouch that she paid to have an expansion charm placed on it (it could now hold a very large amount of things inside and they would be kept safe from the water until she took them out...it had the same charms as the moleskin wallet Hagrid gave her for added security), some new clothes and a camera to take pictures with, Iris found a place where she could slip into the ocean without anyone seeing her.
The fact she barely knew how to swim was a moot point. The main idea behind the act was to avoid drowning, and since she could breathe underwater that meant she could learn on her own time. If not, then she could still try walking.
At least if she made a fool of herself no one would tell about it to the surface dwellers.
Besides, with her new pouch she could acquire a large amount of gold that had been lost to the ocean from centuries of exploration among other treasures.
It would take some doing, and would require the use of several outside parties willing to earn a living for a bit of deception, but the end result would be that even if she was kicked out of the magical world for some made up charge, she wouldn't need them to make a living.
Iris' eyes gleamed. She was going to enjoy summer for once.