Poseidon is one of the Twelve Olympians in ancient Greek religion and mythology, presiding over the sea, storms, earthquakes and horses. 

He was the protector of seafarers and the guardian of many Hellenic cities and colonies. 

In pre-Olympian Bronze Age Greece, Poseidon was venerated as a chief deity at Pylos and Thebes, with the cult title "earth-shaker". 

In the myths of isolated Arcadia, he is related to Demeter and Persephone and was venerated as a horse, and as a god of the waters. 

Poseidon maintained both associations among most Greeks: he was regarded as the tamer or father of horses who, with a strike of his trident, created springs (the terms for horses and springs are related in the Greek language). 

His Roman equivalent is Neptune, feared by those who preside in New Rome.

But there's a title of Poseidon that many have tried to erase.

Father of Monsters.

Many children of Poseidon tended to be monsters.

Either born a monster, made into a monster by the fates, or monsters of their own making.

Chrysaor, the golden swordsman who's renowned for his cruelty as a pirate.

Antaeus, the wrestler giant who had built a temple with the skulls and bones of people he killed.

Polyphemus, an elder Cyclops with a love of meat (but not for animal)

That's to name a few.

Someone who hates Athens and a certain son of Poseidon may also argue that Theseus, in a fashion, can be called a monster, for he deserted a woman who had helped him.

Oh, but my readers.

These previous so-called "monsters" have nothing on the new child of Poseidon.

The Sea God had only ever had one demigod daughter. 

Sons he had aplenty, immortal daughters came up quite a lot. 

But a daughter by a mortal? 

This was rarer than he and his brothers agreeing with one another. 

Perseus Rhea Jackson.

The first demi-god daughter of Poseidon.

Her name belongs to the Son of Zeus,  Perseus who is known as one of the greatest heroes of Greek Mythology.

 He is best known as the slayer of the Gorgon Medusa, a fearsome monster, and as the rescuer of the Ethiopian princess Andromeda.

(He is also the only hero to have a happy ending.)

The daughter of Poseidon is expected to whither under the accomplishments of her namesake. 

But many forget, that even though Perseus was a hero, his name meant destroyer.

(But doesn't it take a monster to defeat another monster?)

Perseus Rhea Jackson's parentage was revealed in Camp Half-Blood after she fought a hellhound and survived.

And it was only then her story began to outshine Perseus, son of Zeus. 

Now whispers follow Perseus Rhea Jackson (Percy, she is affectionately nicknamed by those who have her devotion and undying loyalty) and those whispers revolve around her power.

When going to Camp Half-Blood at the age of twelve, she defeated the Minotaur within the span of a few minutes, whereas Theseus had taken years to hunt and kill the beast.

When she was twelve years of age, she befriended Medusa and still to this day has her as an ally.

A.N. If you watched the series, then you need to understand I was so moved by Jessica Parker Kennedy's performance as Medusa and the way she said she wasn't a monster but a survivor.

At twelve, not only had she won a sword duel against the God of War (Ares, albeit licking his wounds, was impressed but still enraged by the defeat) but she had gone on a quest for Zeus's Master Bolt and survived.

She was still twelve when joined Clarisse La Rue on her quest for the Golden Fleece to heal Tree Thalia and on her journey survived the rage of the sea and held her own in a battle against a fully grown cyclops.

She was thirteen when she was chosen by Zoe Nightshade to join the quest to search for Goddess Artemis of the Hunt and held the sky for minutes after Annabeth Chase had held it for hours - a fact she tells everyone when they inquire about their matching white streak (her grief shook the earth when Bianca di Angelo and Zoe Nightshade had fallen prey to Fate's prophecy)

She was fourteen when Annabeth discovered former camper Luke's plan to use the legendary Labyrinth of Daedalus to invade the camp with Kronos and his army of monsters and sighed (such tiredness for a child that hasn't suffered enough, the Fates crooned in delight) at the inevitability of her and her friends entering the labyrinth themselves to persuade Daedalus to help them instead of Luke.

A.N. I sometimes use Luke as the bad guy for angst and Luke as the good guy for fluff

She was still fourteen when she exploded an entire fucking volcano, just to escape from some fiery telekhines. (Poseidon jolted the oceans with how proud he was at his daughter taking after his title - Earth-Shaker)

At fifteen, when Hera switched Percy and Jason into each other's camps, the demigods at Camp Jupiter proclaimed Percy as Praetor when she successfully defeated Polybotes, a giant. (thus making Percy the only Greek/non-Roman demigod to become a Praetor at Camp Jupiter.)

At fifteen, she decimated 200 undead soldiers of Hades' army in under five minutes. (Hades was not known to be a god that feared others, but he was also not so stupid as to underestimate potential threats.)

You would think Percy Jackson's accomplishments would end there, would you not?

But Perseus Rhea Jackson is a prophecy child and prophecy children die before they turn 16.

At sixteen, she looked at Annabeth with tears in her eyes (but determination burning them away so she could see her (girl)friend's face for the last time ) and shoved Annabeth into Nico Di Angelo's arms and fell into the dark depths of Tartarus.

At sixteen, Perseus Rhea Jackson had walked through Tartarus.

Many would say she lived but did she?

Is living not the same as surviving, they will ask.

You're breathing so obviously you're alive.

But those people do not know of the horrors of Tartarus.

They will not know of Percy's quiet sobs as she curled into herself, crying at the injustice of finding her family and friends and Annabeth only to lose them on a quest for Athena's statue.

Here's a fact about Perseus Rhea Jackson: she will never address Athena as Goddess Athena. 

Not after seeing Annabeth and her siblings in Cabin 6 cry over an arrogant mother who wouldn't shed a tear if they died.

Not after seeing Annabeth and her siblings in Cabin 6 whisper to her in the dark of night of how they wished they could see their mother.

Not after seeing Annabeth hide her pain at her mother ignoring her prayers when they were attacked on the quest for Zeus's master bolt when they were only 12.

12.

They were children and the gods had only given them life so they would grow to become soldiers and die on the battlefield for their God Parents who don't care.

Oh right, where was I?

Right.

They will not know of the desperation of the way Percy had prayed to Ares to take away his curse so she could fight because the time she needed her sword the most was every second she spent in Tartarus.

They will not know of her falling into the River Cocytus.

Cocytus' water is freezing and ice-like and so cold, filled with millions of heartbroken voices as if the river were made of distilled sadness. 

If dipped in, the person's thoughts will become sad and miserable, having no purpose to live: a voice, Annabeth, screamed at her instead of her usual stubborn yet fond voice whenever she talked to Percy.

They will not know of the vicious way she attacked Arachne with Riptide, letting the frustrations she felt at her situation onto the monster.

They will not know of the way she suffocated due to the toxicity of the air and how she crawled on what felt like thousands of daggers to make her way to the River Phlegethon to heal herself.

They will not know what it felt like to be attacked by empousa constantly and eventually dragged away to an arena.

They will not learn of the way she nearly fainted in horror at seeing Antaeus.

Percy had fought him in the Labyrinth, a difficult fight that she had only won by getting Antaeus caught up in chains. 

He was her half-brother, sharing Poseidon as a father, only Antaeus' mother was Gaia. Slight advantage, if it wasn't for the fact he was stupid.

They will never know of the way she revelled in beating him, fight after fight after fight after fight.

Until she lost time.

Until she lost morality.

Until it was only one rule in her head: kill or be killed.

However, he believed her to be cheating so he sent her to be whipped and the Titan brothers, Krios and Koios, whipped her with sadistic glee and enjoyed watching her bleed.

She lost time once more, under the crushing pain of the whips, the knives, the blood loss.

They will never know of the way she screamed at the ghost of Achilles for showing his face and demanded of him to answer her question (Is this what you wished for me? You couldn't handle that a child of Poseidon, let alone a girl had outshone all Greek Heroes from Theseus to you and so you took away River Styx's blessing so I could die in Tartarus? IS THIS WHAT YOU WANTED?!")

They will never know of the way she used her blood (blood-bending) and shaped it to form daggers aimed at the brothers and tortured them until she was strong enough to hold her sword and behead them with vindictive glee.

They will never know of the way she hugged an amnesiac Titan Bob whom she stumbled upon on her escape from the arena.

They will not learn of the tears of relief she had shed after Bob had continued to help her even after he had learnt the truth about Percy destroying his memory.

They will not learn of the stupid ways she had begun to cling to hope at the thought of leaving Tartarus with not only Bob helping her but also the friendly Gigantes Damasen.

They will never learn of the way she had Akhlys begging for her to not kill her while using her own poisonous domain against her. 

They will never learn of the way she grinned evilly at the Goddess of Misery and asked her in a faux-confused tone, "Does Misery hurt you, Goddess of Misery? If it does, let us see how much misery, Misery can take."

They will not learn of the way she drowned the Goddess in the poison she loved to inflict onto others ( because Goddess Akhlys was the Goddess of both Misery and Poison.) and they will never learn of the joy she felt at drowning the goddess and watching as she begged for mercy.

They will not learn of the Goddess Nyx watching Percy's journey through Tartarus.

They will never learn of the offer Goddess Nyx had given Percy. (I will help you get out of Tartarus if you can deceive and kill another goddess, Apate the goddess and personification of deceit and bring me her head.)

They will never learn of the way she completed the task, of the way she out-deceived the Goddess and the way she nearly threw up when she learnt that Apate was Goddess Nyx's daughter.

They will not learn of the way she broke down when Goddess Nyx explained that time works differently and even though it had been 5 weeks on the surface world, it had been 5 years since Percy had been stuck in Tartarus.

5 years.

5 years.

 They will never know the way Goddess Nyx had branded her mark onto Percy's shoulder and then guided the near-comatose girl to the Doors of Death.

They will never know the fear that awoke her when Tartarus himself intervenes to keep Percy from escaping. 

They will know about the unexpected yet much-welcomed rescue of Damasen and the tamed Maeonian Drakon and he, Bob and the Maeonian Drakon hold off Tartarus so Percy could escape.

They will never know of the wrath she wishes to unleash on Athena.

The rage she feels when she sees Hera.

"I can feel the ichor running through your godly veins. I can feel it pulsate with each thrum of your now anxious being. All it would take is a squeeze of my fist and I could have you on your knees begging for me to make it easy on you and turn you into a pile of golden dust. But I wouldn't, no if you achieved your goal and killed my mother, I will make you wish Kronos had gotten to you those years ago." Percy wishes to say to the gods who sneer down at her and vote on whether she should be executed after she defeated Gaea (Not that she'd let them of course, she'd execute Zeus in front of them and then see their arrogance fade) 

Perseus Rhea Jackson has now rejected Godhood twice and fought in the war of the Gods for the last time.

She turns her back on them and then interlocks her arms with Nico di Angelo and goes to see her mother.

She's an older sister.

She'll kill anyone and make them drown in the blood or liquor in their veins if they dare hurt her baby sister.

Her beautiful Estelle.

PERCY JACKSON TITLES: (Let me know if I missed any)

Wielder of Riptide

Seerer of Fates

Retriever of Ares shield

Escaper the Lotus Casino and Hotel

Retriever of the Master Bolt

Retriever of the Helm of Darkness

Sailor of the Sea of Monsters

Retriever of the Golden Fleece

Enterer of the Garden of Hesperides

Bearer of the Sky

Savior of Artemis

Protector of the Ophiotauras

Wanderer of the Labyrinth

Causer of Mt. St. Helen's eruption

Traveller of Ogygia

Witness of Pam's fading

Holder of Pam's spirit

Retriever of the Chariot of Ares

Retriever of the Sword of Hades

Former bearer of the Curse of Achilles

Receiver of Pandora's Pithos and Elphis

Spirit of Hope

Survived sitting on an Olympian's throne

Refuser of Immortality

Retriever of Herme's Staff

The subject of two great prophecies

One of the Seven

Carrier of Juno across the Tiber River 

Former Praetor of New Rome

Drinker of Gorgon's blood

Controller of the Rivers of the Underworld

Survivor of the Death Mist

Nyx's Blessed

Survivor of Tartarus

Defeater of Nike/Gaea

Host of Nekhbet

Defeater of Setne

Receiver of the Crown of Ptomley

The Godkiller