Need help with end boss fight *SPOILERS*

When i start the Cyberdemon fight theres only 4 imps to kill, which is not enough for even one charge of the cube. I've ran around everywhere and no more imps appear at all, what am i doing wrong?

If you use a ungibbable mod you should disable it. The demons need to burn away so new ones may spawn.

More Imps spawned for me...Don't know what I did to make them keep coming. I just kept running around the arena over and over.

Hmm, i'm not using any mods or cheats. And i've run around the arena so many times i get dizzy, only the 4 imps will spawn no matter where i go. My game must be buggin out or something. :(

Ah i figured it out, turns out i forgot that i had the Nitro Doom sound pack installed. I tried again without it and the imps were spawning all the time and the game is now finished. :)

More than imps should be just spawning, maggots and even some wraiths, if I remember, should be climbing out of the Hell hole every time you get to a break in the boulders surround it.