Panzer wrote:Afaik the in-lore explanation of the invocations is just the strong presence of Ethereals and the T'au Soldiers belief in them.
Don't quote me on that though.
It's very likely that GW at that time just wanted Ethereals to give something to make them even more mysterious without ever thinking about having to explain what exactly it actually is. I wouldn't be surprised if they'd eventually tell us Ethereals are low-key psycher....or use some kind of mysterious technology only they know about.
Gotcha, that's what I assumed. It's great to imagine Ethereals- through just loyalty, honor, and oratory- making their soldiers fight harder and better and inspiring them to great deeds. That's what makes Tau such a unique and fun faction. I hope they don't retcon it into something lame like giving the Ethereals a dark (grimdark?) ulterior motive or anything.