Osius stares blankly at Shardorn. "Ok. Magic. Got it."
Hmm.
I will not handle this in the IC thread, as that is not where this belongs. Your characters would all know this information (save that which is specific to the ethereal marauder, but you would understand the general principle behind the idea).
Magic, and psionics, and technology, are all very
different, very
powerful forces. They influence this world more than in any other, because they are greater purposes than good or evil, law or chaos. They are what make the cosmos go 'round.
The phenomenon of the ethereal is not inherently magical in nature. The ethereal and the astral are unique in that they make use of all four forces - magic, psionics, technology, and time - and that they are "neutral grounds" for the four.
Of course, there are other modifications beyond this. Besides
Magical Beasts, there are also
Psionic Beasts. Ethereal Marauders are normally magical in nature - however, given your location and the nature of how they shift, ethereal marauders are psionic creatures, rather than magical. There abilities are psionic, and they exude psionic ability. If the creature were magical, its ethereal shift ability would not work all the time, as the psionic nature of the area would impinge upon magic greatly - it would also be quite resistant to psionics and technology in general (thus, the ectoplasmic missiles from the drilbu probably wouldn't have affected it).
This may not seem like a very important distinction now, but it will become important later on, if you run into creatures that are magical or technological in nature, or even other people who have studied either of those two forces.
Remember...
magic - ignores physical law to achieve its ends;
psionics - finds loopholes in physical law to achieve its ends;
technology - utilizes physical law to achieve its ends.