As seen in Paradise Lost, how do all the devils fit into the Pandemonium?
In John Milton's Paradise Lost, all of the devils exist within Pandemonium. One of the reasons why all of the devils are able to fit within the confines of Pandemonium lies within the meaning of the name itself. Pandemonium is Greek for all of the demons. Based upon this definition, all of the devils and demons are able to fit within Pandemonium based upon the meaning of the word itself.
Second, Milton used the word Pandemonium to define the capitol of Hell. It is this place where the devils and demons retreat so that they will not have to be subjected to God's laws (given the intensity with which they hate God).
Lastly, while the demons and devils are very large, and it would seem that they would all not be able to fit into Pandemonium, the devils and demons are given the ability to shrink so that they can all fit into Pandemonium comfortably.
They but now who seemed
In bigness to surpass Earth's giant sons,
Now less than smallest dwarfs, in narrow room
Throng numberless--like that pygmean race.