Marcos is a military leader in Ming Jol-ik's government.
Chimera Ant arc
During the Chimera Ant crisis, through Morel and Knov, he strikes a deal with the Hunters Association 9 days before their planned attack on the King's palace that if he discloses all military information of the Republic of East Gorteau, he and his family will be able to take refuge in a third country. Morel then tells him to continue his regular daily routine. 6 days before the assault, taking advantage of his duty to prepare 'meat' -- actually beautiful women—for the Secretary of State of East Gorteau Bizeff, he helps Palm Siberia to infiltrate into the palace under the guise of a prostitute.