FREQUENCY: Very rare ([Cold Wilderness Mountains])
FREQUENCY: Very rare ([Temperate Wilderness Mountains])
FREQUENCY: Very rare ([Tropical Wilderness Mountains])

FREQUENCY: Very rare ([Dungeon Level V])

FREQUENCY: Rare ([Ethereal Plane])

NO. APPEARING: 1-6
ARMOR CLASS: 0
MOVE: 15"
HIT DICE: 5
% IN LAIR: 15%
TREASURE TYPE: [C]
NO. OF ATTACKS: 4
DAMAGE/ATTACK: 1-4/1-4/1-4/1-4 or by weapon type
SPECIAL ATTACKS: See below
SPECIAL DEFENSES: See below
MAGIC RESISTANCE: 70% (but see below)
INTELLIGENCE: Very
ALIGNMENT: Lawful evil
SIZE: M
LEVEL/X.P. VALUE: V | 325 + 5

SAVES: 11.12.13.13.14

Xill are bipedal, flame-red creatures, with short, powerful bodies and
four arms, all of which can wield weapons simultaneously. If unarmed,
they figh with four claws for 1-4 HP of damage each.
The high dexterity of the xill not only accounts for its low AC
(its natural AC is 4) but also gives the creature a hit probability of +3 when
attacking (+5 with missiles).

The xill has apparently only one AIM in life -- to produce young;
the creatures are asexual and reproduce by producing eggs which must
gain sustenance prior to hatching in the stomach of a living human <>
or near-human. Thus they will try to snatch victims alive. <near-human=person?>

Xill have the innate power of etherealness. They may transfer from
the Ethereal to the PMP in one segment (6 seconds),
but the reverse process takes two melee rounds. A xill will usu.
initiate an attack by emerging suddenly from the Ethereal Plane near
to a chosen victim, achieving surprise 90% of the time. In attacking,
it will USE two of its arms in an attempt to grapple its victim, while
using the otehr two (which might carry weapons) to subdue.

The subduing attacks are resolved in the same way as attacks to subdue a
dragon. Upon announcement of intent to strike to subdue, all HP
of damage scored by attakcs on the victim (from the two
subduing arms) are considered non-fatal battering/bruising damage.
Each melee round the following fraction is calculated.

                    Total number of 'subdual' HP scored
                        Total number of HP of the victim

The result is converted into a %percentage%, and that is the %percentage%
chance of the victim being subdued in that round. %Percentile% dice
are rolled to determine the result and if the score is less than or
equal to the percentage derived, the victim is subdued.

The grappling attacks are normal; both grappling arms must score a
hit for the grapple to be successful, otherwise it is that the
victim has been able to avoid being grappled. However if the victim
has previously been subdued, the grappling attack will always succeed
in the next melee round. If the xill succeeds in grappling a victim, it
will then inject a paralysing fluid into his bloodstream through its claws,
(normal save applicable) in the next melee round. Victims
grappled thus have one melee round to break free before the fluid is
injected, and they may attempt to do so by 'saving against strength' --
a d20 is rolled, and if the result is lower than the victim's strength, he
has escaped from the clutches of the xill.

In summary, the xill attempts to grapple and paralyse the victim, or
to subdue and grapple him. Once either of these results has been
achieved, it will attempt to become Ethereal (and its power to do so
will extend to its paralysed/subdued victim) and carry the victim to
its lair on the Ethereal Plane to inject the eggs. During this two-melee-round
transitory period when the xill and its victim are turning
ethereal, the xill cannot MOVE, it is vulnerable to magic (i.e. its
magic resistance is reduced to zero) and can be hit by weapons at -3
hit probability. When the transition is complete, however, the
creature can only be attacked ethereally and its normal magic
resistance is restored.

If attacked in its lair on the Ethereal Plane, the first priority of the xill
will be to SAVE and protect its young and to remove any egg-bound
prisoners to a safe place, only then attacking the invaders.

The xill eggs hatch after 1-4 days in the victim's stomach; for the
next 2-8 days the larvae collectively inflict 11-20 HP of damage
on the victim per day as they mature and they then emerge
from the victim, killing him instantly, as 2-16 small xill which grow
rapidly (1-4 hours) into full-sized creaturs.

Protection from evil will always succeed, on either plane, in warding
off a xill.
 

        by Brian Asbury