Ever since he first could remember, Ace saw red.
It seethed across his skin and glowed through his veins at the slightest provocation, causing Dadan and her mountain bandits to scurry away, their own lights flickering yellow in terror.
It was unnatural for a child so young to have only one color, they would whisper, he must be a monster!
This would only enrage the boy more, to the point where he would blast his way through the forest, leaving smashed boulders and splintered wood in his wake.
He was about to fell another great tree, when a light snaked through his own, forcing him back. Ace snarled, looking around for the person stupid enough to interrupt his rampage.
A boy, about his own age with blonde hair and a blue coat, frowned at him, hands sheathed in glowing green. "Hey, I live here! Back off!"
Ace had never met another person with a strong enough emotional spectrum to combat his own, but he didn't think much of it as he attacked the strange boy.
Later, both boys lay bruised and tired on the forest floor.
"You fight pretty good," the blonde panted. "I'm Sabo. We should be friends."
The brunette didn't know what to say, but, for the first time in his life, the haze of red flickered. "I'm Ace."
The two became thick as thieves, literally in some cases as they began to rob the patrons of Goa blind to add to their treasure fund. Then Luffy came, and after an initial rocky start, the third musketeer joined the merry band.
The red spectrum in Ace's heart still flared violently, but Sabo would only counter these outbursts with his own nudge of color. Ace noticed how his friend's spectrum flared from green (when they trained) to indigo (when Luffy scraped a knee and started crying like a baby).
Luffy... his spectrum flared all across the rainbow like a severely spastic butterfly. One minute he would be a solid green charging headlong into a fight, and the next a blinding orange when he caught sight of food.
Then Sabo died, and Ace made a promise.
The red still glimmered beneath his skin sometimes, but he chipped away at it with the impenetrable stubborn emerald of determination. He would become the strongest and freest pirate in the world, and he would protect his baby brother. There was no room inside him for anything else.
When he finally set out to sea, Ace could even pretend that green was his only color.
Meeting Whitebeard was the second most terrifying experience of Ace's life. He had never met someone with such a solidly green spectrum, which smashed through his own light constructs and shields as if they were paper.
The first was when he told his captain about his parentage. That was the only time in his life Ace remembered his spectrum turning yellow.
Pops smiled softly at his silly son, heart glowing a dark blue. "We're all children of the sea," the old man said. All the rage bled out of Ace in that moment, and for once he felt... well he was sure there wasn't a color for it.
Everything would have been perfect, except Thatch was murdered by that no good yellow belly Teach.
His world was consumed by red once more, flaring so strongly that the wooden deck splintered. No one, not even Marco with his cool blue light, could dissuade him from getting vengeance.
Ace later supposed that was what led to his defeat against Teach- he fought with red not green. He was a fool like that sometimes, or so Pops would say.
When all his friends and crew mates came to save him (hearts glowing green- green for him) the young pirate felt numb inside with yellow. When Luffy managed to unlock his bindings, he flew into the fray with green spiked flames. When he lay dying in his brother's arms, all he saw was purple.
"Thank you for loving me," he whispered, heart pounding so hard with compassion and love he thought it might burst, then-
A/N: So this is a kind of character study looking at a 'what if' scenario. Basically, people in the OP world all have visible emotional spectrums, which in the case of very strong individuals can be used like the rings of the DCU's Lantern Corps. In case you coundn't tell, this is based off the ring's powers and spectra.
Here's a breakdown of what the color's mean. More interesting info can be found on the DCU page about the Lantern Corps.
Yellow: Possessed by people who are afraid, or have the ability to cause much fear. Can only be beat by green.
Green: Will, determination
Blue: Hope. Can only have the full extent of their abilities unlocked in the presence of a green.
Indigo: Compassion. Can exert their will on and control others.
Violet: Love, or someone denied love.