Many people equate the word “daemon” with the word “demon”, implying some kind of satanic connection between UNIX and the underworld. This is an egregious misunderstanding. “Daemon” is actually a much older form of “demon”; daemons have no particular bias towards good or evil, but rather serve to help define a person’s character or personality. The ancient Greeks’ concept of a “personal daemon” was similar to the modern concept of a “guardian angel”—eudaemonia is the state of being helped or protected by a kindly spirit. As a rule, UNIX systems seem to be infested with both daemons and demons.
So why are they called daemons and not demons?
Alt spelling.
From https://en.wikipedia.org/wiki/Daemon_(computing)
They’re equated because Christians label all heathenry as demonic.
Tl;Dr It’s the same word but with an æ