Effect: This spell is similar to the fifth level shadow magic spell (q.v.),
but in addition to the quasi-real spells listed thereunder it enables the illusionist to cast a quasi-real
wall of fire, wall of ice, or cloudkill.

Save: If recognized as demi-shadow magic (the victim makes its saving throw),
the magic missile, fireball, et al. do 2 hit points of damage per level of experience of the spell caster,
the wall spells cause 1-4 hit points of damage per level,
and the cloudkill will slay only creatures with fewer than 2 HD.

DMG: This spell also allows the caster to tap a source of power as noted under shadow magic.

Demi-Shadow Magic: There is a bizarre
anomaly here with respect to the wall
spells; victims can take more damage
from making their saves than if
they fail them.  An illusionist has to be <replace with Level Title>
12th level to  have memorised a 6th level
spell; he casts a demi-shadow wall of ice
in the air above a party.  Those who fail
their saves get 3-30 (average
16.5) points of damage and those who
make their saves  get 12d4
damage (average 30 points).  This is
ludicrous, and there is a logical unofficial
change.  Since characters failing a save
against, say, a demi-shadow fireball
take 3.5 points of damage (on
average) per level of the illusionist, and
those who make their saves take 2
points of damage per level of the illusionist
(this is specified in the PH), with
respect to the wall spells one could rule
that damage taken by those making a
save is 4/7 of that which would be
taken by those failing (a messy fraction,
but things are kept consistent).  This
problem obviously requires an official
rule revision, but the suggestion here
makes the effects of this spell uniform
across all applications causing physical
damage.
(Imagine #29)