Soooooo, hi! I just got this idea that had to be taken out of my mind while reading a fanfic about this, so, here's the outline of Percy's character an power. If i'm missing something or calculated wrongly, please point it out.

Servant Stats:

Master: - -

True Name: Perseus Jackson

Alignment: Chaotic Good(Mad)

Classes: Berserker, Caster, Rider, Saber

Epithet: The Titan-Slayer, The Giant-Slayer, Champion of Olympus, The True Hero, Praetor of the Twelfth Legion

Stats:

Strength: B(B+ if in contact with water)(A+ under the influence of Mad Enhancement)
As a Demigod, he is beyond human limits, yet still bound by his mortality as Half-Human, and even beyond that fact, fighting inhumane creatures constantly, from monsters to even Gods, he has built up his strength throughout his life, making him stronger than normal demigods.

Endurance: A(A+ if in contact with water)(A++ under the influence of Mad Enhancement)
Holding the "Curse of the Heavens" placed by Zeus on the Titan Atlas for an extended amount of time, surviving the explosion of an active volcano, and even traversing through Tartarus itself, the husband of Gaea, Perseus has proved time and time again to be beyond pain and able to continue on his goals.

Agility:C(B+ if in contact with with water)(A+ under the influence of Mad Enhancement)
Not the fastest hero known to Mankind, he's still beyond human capabilities, able to outrun trained soldiers easily.

Magical Energy:B(A if in contact with water)(A++ under the influence of Mad Enhancement)
Known to have a deep control over his dominion, Perseus is one of the strongest Demigods thanks not only to his swordsmanship, but also for his complex connection to the sea as a whole.

Luck: D(C if in contact with liquids)
Being a Demigod, his luck was decided by the Fates themselves since birth to encounter every single conflict, for that is the Fate of a True Hero; to fight until the end of his days, and beyond even then.

Skills:

Battle Continuation: B+
As a Demigod who fought thousands of monsters and against The World itself, he is a man that is capable of losing a limb, get his heart pierced, and still continue to fight.

Bravery: A
As a hero who stood face-to-face with beings higher than himself, and as an existence coming from the Sea itself, Perseus is uncontrollable by any means, be it magecraft, pressure or charm, and nothing short of a Command Seal will be able to control him.

Charisma: B
An able leader who inspires hope and determination, he's a man that led multiple armies in his lifetime.

Divinity: A
Born from one of the Big Three and praised by all, be it mortal or immortal, Perseus is a Demigod who is welcomed by those in the Heavens, raising his divinity from the usual B of Demigods to A, comparable to ancient heroes like Heracles or Achilles.

Eye of the Mind (False): B
Made to fight against all odds, Demigods have the innate talent of fighting, giving them the sixth sense they all take for granted.

Instinct: B
As a warrior taught by the goddess Lupa for months, his instincts stem from the teachings of one of the greatest animal hunters in the predatory kingdom; the wolves.

Mad Enhancement: C
As someone who let himself be controlled by his rage when in Tartarus against Akhlys and when battling other creatures, Perseus will grow stronger as the battle goes on, but will slowly start to lose his sanity and consciousness just as well. After passing a certain amount of time outside battle, he will start to regain control over himself. (Bravery is rendered useless after a couple of minutes in battle, when Mad Enhancement starts taking effect. One rank up in all parameters after losing himself in Mad Enhancement.)

Magic Resistance: B+ (A+ in Saber class)
As someone who fought against Immortals that could control Mysteries as easily as moving a sword, and being a Demigod with comparable powers, Perseus has developed a natural resistance to the disturbances in the World, not as strong as it would be in the Saber class

Maiden's Ally: B(Unchanging, regardless of class)
As a hero who helped maidens not by personal desire, but by the heartfelt need to help them, all women will have an amicable vision of them in their minds. Take note that this is not like the Charm skill, for this is not a manipulative ability, but a part of Perseus' legend that is so ingrained into it that not considering it a skill would dirty the legend itself.

Pioneer of the Stars: EX(Unchanging, regardless of class)
As the man who reunited the people of Rome and Greece, who allegedly became sworn enemies for life for desecrating the image of Athena, Perseus became a turning point of Humanity in order to defeat the Will of the Planet, granting him an Ex. Rank in this particular skill.

Riding: A+
As a man capable of riding multiple beasts on the level of the Divine and Phantasmal, Perseus is granted the ability to ride any and all beasts. Of course, as Demigods were unable to interact in a fluid way with any and almost all modern electronics such as telephones and vehicles, in the occasion of maneuvering a modern conveyance, his riding skill will be lowered to a B.

Noble Phantasms:

Legacy of Achilles: The Curse of Invincibility; Anti-Unit (Self) B
Having dipped in the waters of the river Styx, Percy was able to become as invincible as the famous hero Achilles himself. This Noble Phantasm tells his story as a continuation of the Iliad and imbues his body with the concept of "being invincible". As he lost the curse in Roman land, his Noble Phantasm only lasts as long as he is fighting an enemy that is impossible to beat in the eyes of others. (Able to be used by Perseus on all classes).

Anaklusmos: The Sword of the Ocean; Anti-Unit A
A sword passed down by legendary heroes, from Heracles to now Perseus, it's a sword of legend encompassing the experience of all of those past heroes. As part of his legend of being a protector to those powerless, his sword does not harm those that he considers as friends and allies, rendering it as useless as air against them, but at the same time, multiplies his strength times two against those that have betrayed before. His attack rises by 25% if he's protecting someone or something truly precious for him. (Able to be used by Perseus on all classes except Caster).

Son of the Sea: Those that Belong Underwater; Anti-Unit (Self) B
As a Demigod of the sea, all parameters get a Rank-Up while in contact with water, or any substance that has enough amount of both oxygen and hydrogen to be considered a close relative of water. Also, as water is considered his blood and body, wounds are able to heal with proper amounts of water without the need of prana from his summoner.(Able to be used by Perseus on all classes)(One rank higher if in Caster class).

Blackjack: The Jet Black Horse That Flies Between Heavens; Anti-Army B++
As the ever-loyal companion from his youth, Blackjack has advanced to the level of a Phantasmal Beast thanks to the fame of his legend as a fearless mount that accompanied his owner in every journey, from traversing across countries to fighting against truly enormous monsters like Cyclops and Giants, this mare has earned his place as one of the strongest mounts in the records of The Throne of Heroes.(Only available on the Rider Class.)

Mrs O'Leary: The Hound of Hell Redeemed by Heaven; Anti-Army B
A Hellhound that was nurtured and educated by Daedalus, a creator the likes of Nicholas Tesla and Benjamin Franklin admired and deified with time. As a Phantasmal Beast that lived for thousands of years, her strength has matured and grown to reach the likes of Elementals and Pegasi. (Only available in the Rider Class).

The Earthshaker: He Who Controls All Nature; Anti-World A-EX
Moments throughout his life show moments where Perseus unleashed a potential control over his environment that surprised even Immortals, causing earthquakes, tornadoes, storms and all kind of disasters capable of even harming Gaea itself, showing a power deep-rooted within his very soul. As the man who beat The World, he is able to negate/change the "nature" of things because he stole this aspect in his final battle, effectively creating a Miracle out of his own power. This Noble Phantasm is the crystallization of Perseus' potential not as a Demigod, but as a force of "nature" in human form. (Able to be used by Perseus on all classes)(Prana exertion tremendous, taken mainly from Perseus' mana, if not enough, then from Master's prana)(Less mana usage in Caster class).