Luis García Márquez was the human chief engineer of the SS Xhosa serving under Kasidy Yates.
In 2372, Yates ordered Luis to arm weapons when the IKS M'Char approached the Xhosa. (DS9 novelization: The Way of the Warrior)
In 2383, Luis began to temporarily work as the first mate of the Xhosa when Wayne Sheppard was attending his sister's wedding on Alpha Centauri. When Deep Space 9 was being evacuated after Typhon Pact explosives were discovered aboard, García Márquez helped evacuate people onto the Xhosa. After the Xhosa became full of station residents, Yates ordered García Márquez to have the Xhosa depart without her after Kira Nerys convinced her that people on Deep Space 9 still needed their help. (ST - Typhon Pact novel: Plagues of Night)
García Márquez was killed when the Xhosa was destroyed in a collision with a Tzenkethi starship soon after it left Deep Space 9. (ST - Typhon Pact novel: Raise the Dawn)