Crux is the main antagonist of the 2015 puzzle-RPG, Protocol. Created by the one who trapped all of the people in the abandoned laboratory, Crux is responsible for overseeing all of the puzzles and traps that were laid for them, and initiates other devices to try and kill the prisoners and stop their escape attempts. Crux's full name is Adaptable Aptitude Program- CR-VX9, and is voiced by Brian Beacock.
Crux appears on monitors in the form as an animated fox, with orange hair. He wears a navy blue robe with a crescent moon covering the left side of it. He has a patch of white hair surrounding his right eye, with a scar underneath his left. He wears a laurel crown around his head, that pokes around his ears.
Crux is very playful, and loves the thrill of the hunt. He often torment the prisoners through various motives, though he does so only for entertainment, showing a sadistic and somewhat insane way of thinking. At times, Crux also acts very childish; pouting when others get angry at him, and mocking others when mocked himself. Being connected to the central hard drive for the facility, he has records on most events that go on, making him very intelligent.