ussnorway: you always get it from the same place (
a tuff fight at level 12-14)
Actually, I believe it *isn't* a guaranteed drop, so if you're playing Ironman, I would not recommend choosing a setup that relies on getting the drop. I believe it does drop more often than not, so saving before the fight and reloading if you get unlucky enough for it not to drop is a reasonable strategy.
Anyway, one interesting option is to use a different character in the slot, then use the replace character feature to replace that character with a Faerie Ninja once you get the weapon. Physical damage doesn't depend much on level (it's not like magic), and you can use Guardian Angel to keep your new character alive until she is strong enough to not need it. (Also, don't forget about Resurrection, especially if you've reached the point where you have it as a spell, or if you have someone who can use the Amulet of Life; unlike in earlier Wizardry games, there is no stat (or other) penalty for letting characters die and then reviving them.)
Another option is, before you get this weapon, is to give the character the Staff of Doom; it uses the same skill as the Cane of Corpus and is easier to get. Just watch out for the negative health regen and the fact that it is difficult to uncurse.