Disclaimer: I will own Harry Potter when I own the world—that ain't happening any time soon.

Summary: No one realized the significance of his form. AU. Powerful!Harry.

"…but it is the animagus ritual that gives the Celtic warriors their true power. The nature of this magic further merges the spiritual self with the physical self, resulting in the magical ability to transform into the "spirit self" an animal that reflects the personality of the sorcerer. There are others who use variations of this transformation to achieve unity with themselves, and such people are normally more stable and confident individuals. However, only the Celtic have adopted this ritual as a weapon of war. An animagus gains the powers of their animal, even in human form, but it is their state of mind that makes the Celtic so feared and revered as fighters. The combination of human intellect and predatory instinct make them truly devastating warriors, able to fight beyond the limitations of either human or animal…"

Harry, frantically scrambling for every advantage against a far greater enemy, latched onto the passage like a drowning man to flotsam. For over two years now he had immersed himself in training and fighting, seeking and honing all conceivable skills to prepare him for the fight of his life. And it wasn't until he began his quest that he realized just how overwhelmed he was, and how little Hogwarts had prepared him. The Potter Family Library, once he had access to it, looked to be his best bet for finding a scrap of magic Voldemort might not have perfected already. "Secrets of Warriors" caught his eye like a jewel.

Months ago, McGonagall had offered to teach him to become an animagus, but after realizing the time and effort it would take he turned her down. Certainly it would be cool to transform into an animal whenever he wanted, but Harry needed those precious months to hone his fighting skills and learn new ones, not turning his hands into paws. But this passage, translated from a book written by Drusus Peverell, shed new light on the process.

The modern version of the animagus ritual used a potion to find the form. Afterwards the person spent months, even years, learning to wandlessly transfigure each body part into its animal counterpart before attempting the entire change at once. It was slow, time consuming, held little risk for the would-be animagus (despite what the ministry warned), and bore little resemblance to its predecessor.

The ancient method described was quick, painful and legal only because of its obscurity. But it was an advantage Voldemort had never bothered to achieve and that was all the incentive Harry needed to memorize and practice the runes he would need to draw on his forehead in his own blood.

—Scene Break—

A month later Harry made his first transformation and instantly realized why the Celtic warriors coveted this magic. Physical power was key to winning a battle, weak soldiers meant a weak army, it was why every ancient society's military focused on physical training and little had changed that despite the advances in both technology and magic. Aurors and modern militaries still spent months getting their bodies in peak condition. Compared to Harry they would be weak children.

His strength was unparalleled, his speed and reflexes enough to make even quick-draw-Dumbledore look like a clumsy first year in comparison and even his magic was more powerful than ever. And that was just in human form. Of the dark rituals out there, it's the animagus transformation gives the biggest power boost of all. Harry would have laughed if his vocal chords were capable.

Of course it was his specific form that gave him such immense power, and that made three Death Eaters wet themselves. If seeing a muscled warrior abruptly turn into a bear was frightening, no words described the feeling that clamped his attackers still as the massive form of a dragon emerged from Harry Potter.

He grew larger than the buildings that surround him. Black scaled armor covers every inch of his body. Bronze horns erupt from his skull and deadly curved claws replace delicate human fingernails. The curses that forced him to dodge or die as a human are mere insects to the dragon that he has become. For the barest note of time he pauses, regarding them. How fragile humans are, to a dragon, he has never truly realized this before. A cough of flame engulfs the Death Eaters. Ashes stain Diagon Alley's deserted cobblestone.

Many were awed by his form when he first revealed it. Ron, who had taken the potion and seen a lion, looked rather disgruntled while Hermione had regurgitated fifteen different references that proclaimed magical animagi impossible. Everyone chalked it up to the Potter Factor.

But no one realized the significance of his form.

All his life he has fought. Clawed his way through every challenge fate threw at him with little more than guts and fiery determination—as Slytherin as his mind was, the hat sorted him to Gryffindor for a reason. Kept rising no matter how many times he had fallen, because failing was dying and death was not taking him so easily.

First the Dursleys, who had unwittingly taught him martial arts via the sink or swim method. Learn to fight, to use speed and reflexes against greater strength and numbers, or become a punching bag for the bullies of Little Whinging.

And he was no one's punching bag.

Then he found out that the strange things he could do was magic, and he was taken to the magical world. The first book he picked up was one on curses.

Spells to fight.

Even now he is fighting, shifting between human and dragon. Between cursing, hexing, jinxing or ripping Death Eaters apart with swift strokes of his claws, impaling them with his tail or scorching them with his most famous weapon.

He was a natural at defense. Despite the assembly line of abysmal teachers that went through Hogwarts he had scored higher on his OWL than even Tom Riddle.

Perhaps he should send a letter to Voldemort, but it doesn't matter now, the bastard won't live to read it. Shifting to dragon once more, Harry approaches.

Of course even he needed to practice, talent alone wasn't enough to ingrain the reflexive use of curses, hexes and jinxes into his well-honed instincts. But the castle had more than enough empty classrooms—and later the wonderful room of requirement—to cater to his needs.

Harry is a natural at defense, and people were still shocked to see his form.

All magical creatures, the fae, are designed in body and magic for a specific purpose. Goblin magic is built around the craft of stone and metals, and even their bodies are designed for life underground, in tunnels. House elf magic is made to clean and cook and care for the house they make their own, and their eyes are sharp and fingers are dexterous for the tasks that require them.

Dragons are beasts of war. Clad in armor. Armed with teeth, claws, horns and the most destructive of elements—fire. Their magic makes the killing curse look like a joke and only the most powerful wizards and witches can do more than contain them. Even their very instincts are sharpened and polished for the fight. They are—in flesh, magic, mind and soul—warriors.

He is a warrior of prophecy, born and fated to fight. No animal is more fitting.

Charred bones smoke in his wake.

A/N: Harry becoming a dragon/phoenix animagus is practically part of the checklist for powerful!Harry and rarely has any significance in the actual story. Thus I was gripped with the urge to write an anti-cliché fic.