Bard invis works really great in Unrest and Mistmoore vs. undead and
living (although Mistmoore is a strange case, certain monsters are
affected by Undead spells, but Camo can move by them, hmm) but as
Benjamin said it no longer works in Lower Guk on Undead.
Another weird thing is that bard invis doesn't work on greater Kobolds
in Solusek B (35+ dungeon basically) but you can go all the way to the
frogluk king on Live side Lower Guk with it, and unless a shaman froggie
has see invis on you are fine. You can actually stand there admiring the
bok's and frog king (although I'd recommend being careful, in case it
blinked ;)). If I'm not mistaken (and I could be), our invis used to
work against Undead in Lower Guk Undead side, and was changed in a patch
a few months ago. This was even before they fixed Selo's overwriting
Spirit of Wolf.

Ariell Thunderwolf, Karana