Clerics may devote themselves to Deities, powerful beings from the Outer Planes who are more concept than flesh. Druids may seek out such entities as well, but if they should choose, they may serve Nature itself, and it will abide them.

Just as Good is a concept, and Evil is a concept, so is Nature a concept. And just as pure goodness spawns from itself Outsiders, celestial beings composed of the same immortal concept that birthed it, Nature may do so as well. Nature, as a being, however, is a convergence of all of the Inner Planes. Its champions must be created of the same elements and principals as all of the Prime's inhabitants. In a way, this makes them less perfect than their Elemental or Outsider kin, but as any real cutter whose planewalked enough to know the dark of things will tell you, Primes are nothing to be underestimated. Something about short lifespans, hunger, and ignorance makes mortals dangerous folk, and the champions of nature are no exception.

Universal traits of Terrestrial "Outsiders" (unless otherwise noted in their description):
-Monstrous Humanoid Type with the [True Neutral] alignment subtype
--This includes 60ft Darkvision
-Small Size
-Base Land Speed of 30 feet
-LA +0
-One Monstrous Humanoid Hit Die. Unlike other creatures with 1 Hit Die, this die does not go away if they gain class levels. Thus, at ECL 1, they start with 8 (base) hit points, +1 BAB, simple weapon proficiency, (4+int modifier)x4 skill points, and a +2 bonus in two different saving throws (each entry will cite which ones apply). Think of it as Level Adjustment that doesn't suck as bad. (And yes, I know the skill points and saves are different; that's intentional.)
-Class skills for their Monstrous Humanoid Hit Die are Balance, Climb, Escape Artist, Handle Animal, Hide, Jump, Knowledge (Geography), Knowledge (Nature), Listen, Move Silently, Search, Sense Motive, Spot, Survival, Swim, Tumble
-Saving throws from their racial abilities are equal to (10 + 1/2 their character level + 1/2 their highest physical ability score).
-They may speak with their associated animal as with a Speak With Animals spell, and may make Diplomacy checks against these animals as if they had a Druid's Wild Empathy class feature (their druid level equals their character level in this case).
-Automatic Languages: Sylvan and one other. Bonus Languages: Ignan, Aquan, Terran, Auran, Common, Elven, Dwarven
-Favored Class: Druid

Terrestrial Bat

-4 Strength, +2 Dexterity, -2 Constitution, +2 Wisdom
Good Saves: Reflex, Will

Natural Attack: Terrestrial Bats have a natural bite attack that deals 1d4 base damage. When they successfully deal damage to a creature with blood with their bite attack, they heal 1 point of damage.

Wings: At 1HD, Terrestrial Bats gain a +10 bonus on Jump checks. At 5HD, they may fly at a speed of 40ft (perfect) for 1 round at a time. While not flying, they may glide at the same speed, moving 20 feet horizontally for each 5ft they descend. At 8HD, they simply have a fly speed of 40ft (perfect).

Sonar: Terrestrial Bats are blind. Instead, they have an acute sense of hearing that grants them Blindsight out to 60ft. This also gives them a +10 bonus on Listen checks. Listen is always a class skill for Terrestrial Bats.

Screech: As a standard action, Terrestrial Bats can begin an ear-piercing shriek, which requires a swift action to maintain each round after the first. During this time, creatures within 30ft of the Bat are deafened (and for 5 rounds after they leave). Creatures between 30 and 60ft away may make a Fortitude save each round to resist being deafened that round. Bat-related creatures are not affected, though they still find it extremely annoying.

Terrestrial Snake

-4 Strength, +4 Dexterity, -2 Wisdom, +2 Charisma
Good Saves: Fortitude, Reflex
Treat Bluff as a class skill for their Monstrous Humanoid Hit Die.

Natural Attack: Terrestrial Snakes have a natural bite attack that deals 1d4 base damage as well as injecting poison into the victim. This poison requires a fortitude save with an initial damage of 1 Constitution, and a secondary damage of 2 Constitution.

Scent: As the scent special ability.

Lithe and Slithering: Terrestrial Snakes are physically well suited to traversing all manner of terrains. They have a 20ft Climb and Swim speed, as well as a +8 bonus on Climb, Swim, Escape Artist, and Move Silently checks. They are treated as being medium size for the purposes of grapple checks, as well as resisting bull rushes or trips.

Camouflage: Terrestrial Snakes gain a +8 bonus on Hide checks in the environment they were spawned from. Choose one: Aquatic, Desert, Forest, Swamp, Mountain, Plains, Underground. Their hair and skin color will always be indicative of this environment.

Terrestrial Rat

-4 Strength, +4 Dexterity, -2 Constitution, +2 Wisdom, -2 Charisma
Good Saves: Reflex, Will
Treat Sleight of Hand and Disable Device as class skills for their Monstrous Humanoid Hit Die.

Natural Attack: Terrestrial Rats have a natural bite attack that deals 1d4 base damage as well as infecting the victim with Filth Fever. This works just as the normal disease, except the DC of the fortitude save is treated as a special ability of the Terrestrial Rat rather than the static DC is usually has.

Scamper: Terrestrial Rats have a climb speed that is always equal to their base speed, as well as a +8 bonus on climb checks.

Sewer Affinity: Terrestrial Rats have a 20ft swim speed, as well as a +8 bonus on swim checks. In addition, they are immune to all mundane disease, and have a +4 racial bonus on saving throws versus magical disease, as well as effects that sicken or nauseate them.

Bendy Bones: Because of their pliable skeletal structure, Terrestrial Rats take no penalty for squeezing into spaces meant for Tiny creatures.

More possibly.