So.... any other realms of just Sirion?
Regarding SMA and Undead/Daimons/Monsters:
Think of it this way:
Monsters are Giant Wolves, Bears, other animals that seem to have a taste for human flesh. They existed. And all these heraldic beasts we see, which people thought were real or had seen. Just because we know there is no such thing as a Hippogriff, in the medieval world they didnt know, (Medieval I am using would be a decade or two after the fall of the Western Roman Empire - when basically all Civilization had been destroyed and Barbarians were running rampart!), someone claimed to see one and people thought it was real.
The Monsters of the Dark Ages were real to the people of the time.
Undead? Plenty of fear and scaremongering about Undead, even up to the Renaissance and afterwards. (Heck technically it isnt impossible either - all those Zombie films *could* turn out to happen one day with our advances in Technology and Medicine and Dirty Warfare! As for Vampires, plenty of people have an allergic reaction to sunlight, its a medical condition called photosensitivity. There is also a "lifestyle", as some idiots have called it, called Vampyrism where they people call themselves Vampyres and split themselves into three general groups: Sanguine, Pyschric, Hybrid. The First and third actually do drink blood. The second and third use Psychic Draining. A Hybrid does both ofc.) What else.... a Stake through he heart? Pretty sure that will kill anyone. Beheading? Same. Garlic, Crosses etc? Hollywood bullcrap. Although some Satanists from the Satanist Church claims that beholding a Cross or actually holding one hurts them, all in there head if you ask me. Note that The Church of Satan has never made such a claim. (Yes they are two different churches) and someone somewhere must be allergic to garlic!)
This leads to Daimons... ask Daemons. Or Judeo-Christo Demons, Devils. Please note I make a very clear division between Fallan Angels (Demons and Devils) and Daimons/Daemons.
In my opinion, the Daimons are more related to pagan Daimons than Judeo-Christo Demons. IE: Not necessarily demonic, anti-god, malevont, turn you to the dark side and more Something old beyond words, of all shapes and sizes, some are Malevont, some are good, etc etc. Another word for Spirits. Infact if you played DA:Origins, then the Fade Demons and Spirits I would say is more related to BM Daimons (at least on Dwili) than the Judeo-Christo version.
Medieval times: Demonic Position was BIG. Inquisitors, Exorcists, Templars, Heretics, Witches, Warlocks, Saracens, Muslims, Heathens, Pagans, Jews...... The first two obviously root out 'Demonic influence' that was in all things to do with the everything after Exorcists.