Frank: Frank likes brown. Not plain old ordinary brown, but rich, warm brown. Like Hazel's skin. It's not a flashy color, but it's steadfast. Loyal.
(The color of a charred piece of wood)
Hazel: Hazel likes yellow. It's the color of the curtains that used to hang in her mother's kitchen when she was very young, before the bad days. It's the color of the sun. It makes her happy, and Hazel will take all the happiness she can get in this world.
(Before she has to leave it again)
Piper: Piper favors purple. Not pink, like most of her sisters, purple. Pink is for little girls, little, helpless girls. Like Piper used to be. Purple makes her feel powerful. Like she could be a queen.
(Queens are known for more than their beauty, after all)
Annabeth: Annabeth's favorite color has always been red. It's the color of passion, yes, but also of strength, and unity. It's the color of the flower Luke gave her when she was a kid, when she wouldn't stop crying. Annabeth forgets that it's also the color of blood.
(She will never forget again)
Leo: Leo's favorite color is orange. It's a bright color, loud, full of energy, but out of place. People like yellows, and reds, blues and greens, but orange? Nobody knows where orange is supposed to fit.
(Nobody knows where Leo is supposed to fit)
Jason: Jason thinks blue is probably his favorite color. Blue like the sky, like Thalia's eyes, like his own. Blue is freedom, the weightless uncaring of a summer day. Blue is also loneliness.
(A child of two worlds will never belong in either)
Percy: Predictably, green is Percy's favorite color. It used to be blue, but when the ocean is your primary source of power (of life), it's hard not to get attached. But green is also the color of rebirth, and of self reflection. The color of the earth.
(Percy doesn't love green so much, anymore)
Nico: And Nico? Well. Nico's favorite color used to be white, because if you took it and refracted it you would see an entire rainbow. Now, Nico gravitates towards black. Black is the absence of color. It hopes for nothing, and expects nothing.
(It is as cold and dark as the underworld itself. As cold and dark as Nico di Angelo, son of Hades)