The Warrior

There once was a warrior, the strongest in the land. Each day he would go out with his sword, find some troublesome spot within the kingdom, and solve the situation in the only way he knew how.
Many admired his skill with the sword.
Others feared where such skill might one day lead him.
The day came when word of a dragon in the kingdom reached the warrior. According to the rumor, a dragon had taken residence atop the royal tower wherein the king's eldest (and most beautiful) daughter spent her days deep in reflection.
Not wishing the princess to be harmed by such a dangerous beast, the warrior journeyed to the tower with sword in hand.
He met several singed knights on the way, each warning him of the dragon's might and how it refused to abandon its perch atop the tower. A few also mentioned how the dragon would not attack until provoked, and so the warrior thought deeply on how to utilize the information.
Upon reaching the tower, the warrior climbed the outer stairway until he reached the observation deck; where the dragon was curled around the tower in supposed slumber.
There was no sign of the princess, and the warrior hoped he was not too late.
The battle with the dragon did not take long, for though the beast was powerful, it seemed incapable of any deadly blows.
Perhaps it was sick? It did not matter. The warrior merely took the dragon's weakness as motivation not to falter as the knights had.
He would not flee from a singeing, if it meant rescuing the princess.
And so the moment came when the warrior gained the advantage, and plunged his sword deep in the dragon's heart.
At the moment, the dragon shuddered.
But death thralls did not follow. Instead, the dragon's shudders caused its form to blur, and suddenly it was the princess  who was before the warrior, his sword thrust through her chest.
The princess's dying breaths painted a picture of mage-craft gone wrong,  being stuck in a shifted form, and barely controlling the wild instincts of of her new form.
The was no condemning the warrior for his killing blow, though his heart ached at having struck down an innocent.
The princess died.
The royal family, not wishing to tarnish the people's memory of their daughter by revealing her dabbles in forbidden mage-craft, spread a tale of a hero who managed to drive off the dragon, but not before one of its sharp claws (so much like swords in their sharpness) pierced the princess's heart.
And the warrior?
He went to his home, hung his sword above the mantle, and never again took it up.