If you call on spirits under a specific mask, in this case presumably Joy Of Satan, you’ll probably see them show up looking blond, the same as the Imperial Arts author sees demons looking ugly and weird, because he’s a grimoire trad. guy.
I don’t place expectations on them, and they take all kinds of forms for me, including totally non-athropomorphic.
Same with angels - you go to them assuming they’re these bad guy hustlers, you’re going to limit what you get.
You know how, to get online and view a website, you need a program called a browser?
You can set browsers to make all the text on sites come out a specific way, you can block javascript (which gives a lot of the interactive functionality & other aspects on a web page, and blocking it can totally cripple the way some sites display) - and the belief you take to any magickal interaction seems to be like that.
It seems to affect what kind of manifestation you get, including limiting some of the ways the spirit will act, or what it will say to you.
Note that even with 25+ years experience in magick, I’m still only saying “seems to be” because I wouldn’t presume to know it all.
So, belief isn’t a passive thing, in magick - it can affect what you get delivered to you!
This is the part where your own power as a magician comes into play, and if you hand that right to define spirits over to other people, who have disempowering stuff woven into their system right through (Imperial Arts no less, in his own way, than JoS), you may end up limiting what you get, just like using NoScript to block all javascript at all times.
Meanwhile, here’s a fine upstanding chap who will block all Abrahamic faiths and the energies associated with them: The Demon COHZIER.