Contrary to what Webster 1913 thinks (just see what he thinks The Web is...), daemons have little to do with demons, and a lot more to do with gremlins. These were the little people who made things go in Ancient Greece, whereas the gremlins were the little people who made things stop in the RAF. Which is a Bad Thing at any number of hundred feet above ground level.
The name now has more connotations with the computing world, however. But if you're using DOOM as a system administration tool, you get to waste those daemons with a chainsaw, bloodied fist and plasma launcher.