Quibble/additional obsevration: Icke mentions a being with "two frequencies" and that sometimes they appear to us when they choose to use "our" frequency. I posit that rather than a finite number of "frequencies", some (or all) beings operate across a span of frequencies, with the more "advanced" having a wider range that others. Much like a dog sees wavelengths of light that humans cannot.

Now let's add a little "Flatland" to that. Maybe all beings operate across a frequency range, and those outside of one's own range seem "preter-natural" or "extra-dimensional". So then, we humans may seem "preter-natural" to those with an even lower frequency range than us. So, how do those with narrower frequency ranges appear to those enjoying a wider frequency range?

"NPC's". All beings have existence universally, but all of us with limited frequency ranges may operate only in the range which may attune. In other frequency ranges, we may appear as something inanimate or at least quite inconsequential to those enjoying those ranges. What would be the "lower frequency entities" in our own frequency experience? It could be our fellow humans - maybe "NPC's" are real, but another possible explantation could be:

"dark matter".

Just spitballin here. :)