Background:
Diving into the seas without any proper equipment, and armed with only a simple fishing spear, this beauty glides through the waters with unparalleled confidence. “There's no need for those things,” she says, claiming that even the mightiest monster of the sea could never hope to harm her.
In spite of her stunning appearance which gives off a 'lovely princess from a faraway kingdom' kind of vibe, they have a ferocity like a lion, skill like a soldier who has trained for two and half lifetimes, and speed that defies the ability for someone to even process with the naked eye.
You see, the reason for that is because this summer maiden is actually the legendary hero Achilles, the greatest warrior of the Trojan War. Though hold on a second, why is he a woman!?
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When Achilles was still young, his mother asked him which he'd prefer, “a long and peaceful life without being remembered by the masses,” or “the short life of a hero with brilliant accomplishments in battle?” Ambitious, the young hero chose the path of glory, and trained to be a great warrior, even being taught by the centaur Chiron, who had taught many other great heroes before him.
However, though he was more than prepared for his fate, his parents decided to intervene on his part and chose to hide him away in the land of Skyros, amongst the daughters of king Lycomedes. There, Achilles took the name Pyrrha, and was hidden from the rest of the world.
Sadly, the world came looking for him anyway.
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The reason for Achilles current form is because of a third Noble Phantasm, Pyrrha stí Skyros. A blessing placed on him by his mother, it changed his form into that of a woman to better hide him amongst the daughters of Lycomedes. It protects his identity, obscuring the information of his Status, Personal Skills and Andreias Amarantos. However, as a price, his physical parameters have received two ranks down from what is actually shown, and most of his other weapons and Skills have been sealed away.
Naturally, using Skyros Choreftría Komētēs will instantly expose his identity, and all information will be properly corrected. On that note, it will also give him back one Rank in each parameter.
Ideally, it's a tool perfect for an Assassin, but maybe because it's summertime, or because his mother is being overprotective again, it activated without his consent when he manifested as a Lancer. Also, since Pyrrha was also the name of a woman who survived the Great Deluge which destroyed the Bronze Age, using Pyrrha as his name will not reveal any information to enemy Masters, and may even produce false information to confuse them. This also causes his hair to appear red when active, though that really doesn't matter.
Since it's a mystery that formed during a summer break, it also gives him benefits similar to Natural Body (Sea) at A-Rank.
Personality:
Their attitude is mostly unchanged from their Rider self, being a hotheaded, confident hero who has no qualms about flirting around with attractive women. And yes, that last part has definitely not changed just because their body is that of a woman’s now…
"Well actually, maybe if Patroclus was here---"
In spite of that, they've taken this chance to just throw away the burdens and thrills of a supreme warrior, and are instead enjoying the thrills as a supreme ocean diver and beach beauty. They've taken this as a great opportunity to just live normally. But be careful, that spear of hers is still dangerous, and she has a tendency to become combat ready at the slightest provocation.
... Well, in truth, there is some other changes. Likely due to his identity being changed from "Hero of the Trojan War, Achilles" to "Princess of the land of Skyros, Pyrrha," he's also developed some interests in more traditionally feminine activities. Mostly clothes shopping, appreciation of fine jewels, and worrying about whether his weight has changed uncomfortably, or if his muscles aren't as defined as usual, or if his spear is really any good. You know, girl stuff.
Wish for the Grail:
Their desire seems to be evenly split between the glory of a famous warrior, and the pleasantness of a normal life. Perhaps, during that time as “Pyrrha” he obtained an appreciation of the mundane and simple lifestyle of someone who isn't always training and fighting. On the beach, this desire is most greatly conflicted, as memories of the battles of Troy linger in the foreground, even while just fooling around at beach houses.
This may also be why their Luck has gone up, as they may be subconsciously trying to reconcile the two wants, and are trying to find a compromise between them.
Though, it does seem strange that this contradiction only manifests when he becomes "Pyrrha." And no one is willing to ask him outright why. Probably cause they don't want to get dragged by him into a 'swimming race.'
Relationships
Atlante:
“Yo, big sis, I was wondering if you'd appreciate some Scylla meat I managed to get? Eh, why are you looking at me all horrified like that?”
Tamamo Lancer:
“I can't stand her, she gives me a feeling like that flighty sun god Apollo! It's fine if I hunt her, right? She calls herself a shark, so it's fine, right?”
Penthesilea:
Currently swimming circles around each other, like a pair of sharks sizing each other up. But what kind of prey are they respectively going for?
Hector:
“The warrior prince of Troy. Compared to his pathetic wimp of a brother, an exemplary fighter. But jeez, he looks like he seriously needs to loosen up. This is supposed to be a vacation after all, not a death match.”
Orion:
“Darling---!"
(She just threw him at a massive shark)
Likes: Patroclus, big sister types
Dislikes: Mother's protective meddling, fancy looking weapons
Talents: Destroying all current swimming records
Natural Enemy: Odysseus