The Banshee is a well-known myth/tradition, known to
every Irish person. Her name is, literally, 'woman
fairy', and her haunting wail (perhaps derived from
some sound of the wind on a stormy night) was believed
to be a harbinger of death, which means that she should
in fact precede the battle.
However, if someone had already died, and the banshee
was heard, it was believed more death was to come, and
if that is the intended message, it is deep and subtle
indeed. The sound of the Banshee was closely linked
with the sighting of the 'will-o-the-wisp' a phenomenon
of marsh gas that appears as a misty white 'wisp'
floating above the bog, and that is perhaps alluded to
in the presentation of the Banshee here, with her white
gown and the mists of dry ice around her.
This is a traditional Irish melody from unknown origin
and was originally written for celtic instruments.