"AND THE LOOM OF FATE"
In the season finale for the series, Colonel Baird and alt dimension Finn Carsen [who had never become a Librarian] jumped from one alternate reality to the next to meet those incarnations of the Librarian. Each one of them was a counterpart to one of the three apprentice Librarians from Earth Prime-Time:
1) Jake Stone, a derring-do adventurer in an anarchic world of wild magic and constant war
2) Ezekiel Jones, a techno-mage for a world in which the world's population had been possessed by the spirits of the dead
3) Cassandra Cillian, a sorceress whose world had reverted to the Old Ways and the dragons had awakened to rule the skies
Techno-mage Ezekiel's laboratory/stronghold was that world's last bastion against the hordes of the undead who had the place surrounded. As he gazed out at them, moaning their desire to possess them, Ezekiel muttered:
"Sod off, Deadites."
"Deadites" is a term coined for the "Evil Dead" franchise. Here's the description from the Evil Dead Wiki:
A "Deadite" is a life-force, person, animal or plant possessed by a Kandarian Demon. They are described as evil demonic zombies and are the main antagonists of the Evil Dead Franchise. Their disembodied forms are rarely shown, notable examples being when the evil was put in the "world of the flesh".
Many times I will take a tossed-off comment in a TV show about some fictional character from a different medium to mean that what was being referenced actually did exist in the TV dimension. With many references this is easy to enough to make convincing because they are references to characters who existed already in TV anyway - Superman, Batman, Indiana Jones, Methuseleh.
But in this case, I don't think Ezekiel's epithet is proof that the characters of "The Evil Dead" existed in Toobworld. For Earth Prime-Time, Bruce Campbell is Sam Axe, not Ash Williams.
I've looked through the other TV shows which have mentioned "The Evil Dead" and none of them treated the movie as if it was part of their world.
- 'Stargate SG1'
- 'Buffy the Vampire Slayer'
- 'Ghost Whisperer'
- 'The Goldbergs'
So this is just a case of Ezekiel being familiar with the movie and basically quoting from it. He was using "Deadite" as a comparison, not actually claiming that these ghouls were possessed by Kandarian demons.