Argh, I typed up my rough draft and formatted it for the forum, and then my post was eaten. Here's the rough draft (made before I saw the post about druids and metamagic--I might ask the player whether she'd prefer metamagic feats instead of the "Mark of" bits I added).
-----
Servant of the Elder Forest
Hit Die: d4
Requirements
To qualify to become a servant of the elder forest, a character must fulfill all the
following criteria.
Knowledge (Nature): 8 ranks.
Knowledge (The Planes): 8 ranks.
Feat: Alertness
Spells: Ability to cast at least one Divination spell an dat least one summoning spell
of 3rd level or higher.
Special: Prior contact with a servant of the elder forest or a pseudonatural creature.
Class Skills
Concentration (Con), Gather Information (Cha), Handle Animal (Cha), Knowledge (Int),
Listen (Wis), Profession (Wis), Scry (Int), Speak Language, Spellcraft (Int), Spot
(Wis), and Survival (Wis).
Skill Points at Each Level: 2 + Int modifier.
C. Lev. BAB Fort Ref Will Special Spells per Day
1st +0 +0 +0 +2 Summon alien +1 lev. of exist. class
2nd +1 +0 +0 +3 Alien blessing +1 lev. of exist. class
3rd +1 +1 +1 +3 Mark of the supplicant +1 lev. of exist. class
4th +2 +1 +1 +4 Mad certainty +1 lev. of exist. class
5th +2 +1 +1 +4 Pseudonatural companion +1 lev. of exist. class
6th +3 +2 +2 +5 Extra summoning +1 lev. of exist. class
7th +3 +2 +2 +5 Mark of the chosen +1 lev. of exist. class
8th +4 +2 +2 +6 Insane certainty +1 lev. of exist. class
9th +4 +3 +3 +6 Timeless secret +1 lev. of exist. class
10th +5 +3 +3 +7 Transendence +1 lev. of exist. class
Class Features
All the following are class features of the servant of the elder forest prestige class.
Weapon and Armor Proficiency: Servants of the elder forest gain no additional
proficiency in any weapon or armor.
Spells per Day: When a new servant of the elder forest level is gained, the character
gains new spells per day as if he had also gained a level in a spellcasting class he
belonged to before adding the prestige class. She does not, however, gain any other
benefit a character of that class would have gained (improved chance of controlling or
rebuking undead, metamagic or item creation feats, hit points beyond those he receives
from the prestige class, and so on), except for an incresed effective level of
spellcasting. If a character had more than one spellcasting class before becoming a
servant of the elder forest, she must decide to which class she adds each level of
servant of the elder forest for purposes of determining spells each day.
Summon Alien (Sp): When a servant of the elder forest casts any summon spell, she
summons a "pseudonatural" version of a creature chosen from the appropriate list on page
287 or 288 of the Player's Handbook. For example, by casting summon nature's ally VI,
she could summon a pseudonatural dire bear. This adds the pseudonatural template (from
page 47 of Tome and Blood) to the summoned creature. If the selected creature would
normally be celestial or fiendish, the pseudonatural template replaces that template.
Alien Blessing: An alienist applies a +1 insight bonus on all saving throws, but she
permanently loses 2 points of Charisma.
Mark of the Supplicant: At 3rd level, when the servant of the elder forest takes an
alternate form (such as a druid's wild shape or through a polymorph spell) he can choose
for the alternate form to have a grotesque, disturbing appearance. Enemies receive a -1
morale penalty to their attack rolls when attacking the servant of the elder forest in
this alternate form.
Mad Certainty: At 4th level, the servant of the elder forest's mad certainty in the
power of entities beyond the reach of normal space and time lend her an unnatural
fortitude. She gains an additional 3 hit points as though from the Toughness feat.
However, constantly dwelling on such beings is mentally corrosive, and the servant of
the elder forest's mind begins to fracture. She develops a phobia against a specific
kind of creature, suffering a -2 penalty to saving throws, attack rolls, and
Charisma-based skill and ability checks in regard to these creatures. The selected
creature gains a +2 morale modifier to AC and saving throws against the phobic servant
of the elder forest. The DM determines the creature feared.
Pseudonatural Companion: On reaching 5th level the servant of the elder forest's animal
companion, if any, gains the pseudonatural template (see Tome and Blood page 47) in
addition to the powers and abilities normal for a familiar of the appropriate level.
This does not replace the animal companion--the original slowly takes on pseudonatural
aspects, which become fully active at this point. From this point on, newly gained
animal companions already possess the pseudonatural template.
Extra Summoning: From 6th level on, the servant of the elder forest gains one extra
spell slot at her highest spell level. This slot can only be used for a summon nature's
ally spell. As the servant of the elder forest becomes able to cast higher-level
spells, the extra slot migrates up to the new highest level.
Mark of the Chosen: When the servant of the elder forest takes a grotesque alternate
form (see Mark of the Supplicant, above), she gains damage reduction 10/magic,
electricity and acid reistance 20, and SR 25 while in the alternate form.
Insane Certainty: At 8th level, the servant of the elder forest's mad certainty
crystallizes into a truly chilling mania. She gains an additional 3 hit points as
though from the Toughness feat, but her phobia likewise intensifies. All penalities and
bonuses listed under Mad Certainty for the selected creature increase to -6/+6.
Timeless Body: At 9th level, the servant of the elder forest learns the secret of
perpetual youth. She no longer suffers ability penalties for aging and cannot be
magically aged (see Table 6-5: Aging Effects on page 109 of the Player's Handbook).
Any penalties she may have already suffered, however, remain in place. Bonuses still
accrue, but the servant of the elder forest is stolen away by horrible entities when her
time is up, and she is never seen again.
Transcendence (Su): At 10th level, the servant of the elder forest, through long
association with alien entities and intense study of insane secrets, transcends her
mortal form and becomes an alien creature. Her type changes to "outsider," which means
(among other things) that she is no longer affected by spells that specifically target
humanoids, such as charm person, but she can be hedged out by a magic circle against her
alignment. Additionally, the servant of the elder forest gains damage reduction
20/magic and electricity resistance 20.
Upon achieving transcendence, the servant of the elder forest's appearance undergoes a
minor physical change, usually growing a small tentacle or other strange addition or
substitution, such as an extra appendage, organ, eye, or enigmatic lump. The servant of
the elder forest can hide this abnormality in a robe or hood, but the alien growth is
not under the servant of the elder forest's control and sometimes moves, twitches,
opens, or otherwise animates of its own accord.
Anyone who shares the servant of the elder forest's predilection for supplication to the
Far Realms immediately recignizes her transcendent nature, and she gains a +2
circumstance modifier on all Charisma-based skill and ability checks when interacting
with such beings. She gains a +2 circumstance modifier on Intimidation checks against
all other creatures to whom she reveals her abnormal nature.
-----
Comments are quite welcome, of course, especially on the Mark of the Supplicant and Mark of the Chosen features. They're an adaptation of the pseudonatural template intended for the druid's wild shape, but I'm not sure how balanced they are.
-Adrienne