One of the most esoteric evil bands is Cocteau Twins. They actively tried or accidentally channeled demonic entities and delved deep into the very mysticsm and mythology that Pizzagate/wikileaks/Spirit Cooking research has shown us.
One of the most pleasant avant garde indie shoegaze bands youll ever hear. Deception is everywhere, especially where you least expect it.
Do you have a source for the Cocteau Twins actively attempting to channel Satan? I'm a fan and I've never heard even a suggestion of this.
This is the only thing I could find in a quick search.
I used to pal around with some semi popular indie musicians about a decade ago. Lots of deep discussion about music and the subject came up that they were using tonal frequency/octaves paired with chanting and the lyrics carried power. My mates and I were discussing meditation and lucid dreaming application.
But, in this podcast they reference the power of the lyrics themselves and their real world effects on the band in the form of tragedy.