This does, incidentally, make R'lyeh Dreamlands quite dangerous to AE Ermor; all those not completely sane H1 cultists have a tendency to prophetize to H3 gibbering cultists.
So not only is there the usual mindblasting against the commanders (mitigated by using ghouls and generic living militia), but there's yet more banishment spamming...
Void Spectre is, so far, the only non-Pretender, non-Gift-of-Reasoned void commander I've found so far. Nasty pieces of work, them.
That national dream-hunting spell... is not in the manual. Looks to be a far safer version of Mind Hunt, 'tho, in that you can still nail astral nations with it, and you can equip your mage accordingly (hm: can he enslave and bring him back?).