The Secret Service
The most powerful, well connected, and physically skilled agents of Columbia, the secret service also has the duty of guarding the nation's president. That's their main goal, at least. They also maintain national security in the more civilized parts of the nation. A refined counterpart to the Columbian Marshals. Their organization is a carryover from an old-world group of the same name or is inspired by it, the records are sealed on that and every agent seems to have a different idea on its founding. A far more restricted organization, comparatively, the current iteration has pretty much cart blanche to do what they believe necessary for the nation. Appointment to the Secret Service is a great honor, as well as an inhuman trial. Once selected from the Colombian armed force, prospective undergo a year-long trial attempting to weed out the weak and the unskilled. They fight each other in mock battles, live-fire exercises, and hand-to-hand brawls. They're sent out into the wilds to survive on their own, with nothing but a handgun and a single magazine to provide for them. They're even tasked with infiltrating gangs and tribes to dismantle them from within. By the end, 10% of prospectives will have perished in their attempt. The next 25%, crippled beyond usefulness. 40% will have straight up quit (more often than not leaving the armed forces completely). The remainder can start training. Another year will pass as the neophytes will be taught the vital skills needed to be proficient in their office. Personal combat, ambush tactics, information gathering, espionage. Each one taught clearly and consicely, with no room for error or misunderstanding. Once that course has been completed, the prospectives still might not make it, as their final trial is the last hurdle, and it's a big one. They are tasked with protecting the president for a single night, alone, and with little outside support. Don't worry, other more experienced agents remain near the president, just out of sight. If the new class of agents can get through the night, any traps set by the instructors, and without interrupting the president's night, they've finally made it. Their induction is short and private, and their adding to the ranks of the Secret Service happens without preamble.
Their exact number is unknown, though generally accepted to be bellow one thousand. They operate alone, or in small teams at any time they don't have protection duty.