Programs (Angel Beats!)

Programs (originally called NPCs in the past) are the collective term used by the SSSR to refer to the majority of the population that reside in the Afterlife School. They have many characteristics similar to a real person, but they are distinguishable by their ability to easily recognize persons who have recently arrived in the Afterlife. 
Similar to humans in the Afterlife, Programs do not age but a notable characteristic that sets them apart from real humans is that they do not possess souls, and anything weird they see is suppose to be normal (i.e seeing the SSSR with guns and commenting that they are just fake guns).
It is unknown if a Program could be revived if they were to be killed. Even Nick was unsure if they could be revived like regular humans in the purgatory world.