Agent 13 is an agent of the Activity Consortium sent to Mayview to look over the Ghost Train with Mina Zarei and another unnamed agent. 13 has the distinction of being the agent responsible for the Ghost Train's demise and trapping the main cast inside the Mayview barrier.
13 and another fellow agent were watching over the Ghost Train with Mina Zarei during the night of the Activity Club's meet-and-greet with Agent Day. When the Train eventually returned to their camp, the three were unaware of the events that had unfolded outside the barrier, and so Dr. Zarei removed one of Day's Love Arrows from the Train's smokestack. This unwittingly caused the Train to enter a feral state and forced Agent 13 to use her tool to quickly defeat the locomotive. While this stopped the Train's rampage it had the unfortunate consequence of eliminating the only way for spectrals to enter or leave Mayview and trapping everybody inside until the Train fully healed itself.
Agent 13's tool is a dinosaur-shaped grabbing toy that grants her the ability to manipulate objects at a distance, akin to the act of pretending to smash distant objects between one's fingers. This power was capable of smashing the metal Ghost Train between its jaws without any resistance, so the ability's raw strength is presumably immense.