In that instant, everything that the zero fought for disappeared from his thoughts. No longer did he seek fortune or fame. He wasn’t dancing on the border of life and death for honor or coin. He was only fighting to protect his comrades.
With his mind clear and his heart pure, he slayed the beast and became a hero.
According to Mark Rosewater, the fight mechanic would have white as its tertiary color. Plus, this card is about heroism, which is very white. Source
This came from a design that I had drafted up a year ago during an intense game of EDH where I was playing a Azami, Lady of Scrolls No Fun Allowed deck. I was essentially one turn away from pulling off an infinite turn combo to let me win, and I burned through numerous spells to prevent one of my friends from pulling off the Exquisite Blood + Sanguine Bond, especially since I had less than 10 life. I dropped counterspells, time stops, all that fun stuff. In the end I still lost, by one turn.
It did get me thinking of how blue would prevent damage in their color. I believe that since blue is often associated with time manipulation, blue would prevent damage temporarily, but would eventually take the full brunt of the damage.
His comrades, having finished the battle, went to retrieve the bodies of their fallen comrades. And there, by the shore, they found him. A lone flame sprite held his hand, staying with him until his final moments. He died with a smile.