Student of the Five Elements

(A monk prestige class.)

Not all monks devote themselves wholly to the study of Ki, and the benefits it brings. Some turn their attention to external energies, like the five elements which comprise the universe (in their worldview); earth, air, fire. water, and wood. They must have learned a great deal about the mystical universe, and about the elements of their own body, before entering this class.

Prerequisites: Knowledge (arcana) 9, Purity of Body

BAB: +3/4; all good saves; 4 + int skill points; skills as monk; d8 hit dice.

Class abilities
1 Monk abilities
2 Secret of the Elements
3
4 Secret of the Elements
5
6 Secret of the Elements
7
8 Secret of the Elements
9
10 Secret of the Elements

Monk Abilities: Levels in this class stack with monk levels for purposes of AC bonus, unarmed damage, flurry of blows, and speed.

Secrets of the Elements
There are many secrets of the universe which can be learned. They are learned like talent trees in d20 modern, or feat chains. At each even level as a Student of the Five Elements, the character can select one of the secrets that they qualify for.

Earth Secret Chain
Knowledge of Earth (Stability): Whenever the character must make an ability check to oppose a trip, bull rush, or overrun attempt, he gains a bonus equal to his character level. In addition, his weight limit for encumberance is increased by 50%, and his speed is not reduced for wearing medium or heavy armor. He gains the ability to speak Terran.
Prereq: none.

Earth Body:
The student's body takes on the quality of the earth and stone he studies. He gains DR X/-, where X is 1/2 his character level.
Prereq: Knowledge of Earth

Earthen Mind:
The student learns to control the earth around him. He gains spell-like abilities based on his class level. They can each be cast 1/day, with caster level equal to his class level; the save DCs are wisdom-based.

1-2 Magic Stone
3-4 Soften earth and stone
5-6 Stone shape
7-8 Spike Stones
9-10 Wall of Stone
Prereq: Earth Body

Earthen Form:
The character can assume the form of an earth elemental of his own size or smaller, and back, 1/day, like a wild-shaping druid of his class level.
Prereq: Earthen Mind

Mastery of Earth:
The character becomes an elemental creature. He is treated as a native outsider, gains DR 10/magic, can take on his earthen form 3/day, and it can be one size larger than his original size.
Prereq: Earthen Form

Water, Air, and Fire chains

Water Secret Chain
Knowledge of Water:
A bonus to swim checks equal to his class level, and the ability to speak Aquan.

Watery Body:
The character gains a dodge bonus to his AC equal to 1/2 his class level.
Prereq: Knowledge of water

Watery Mind:
As Earthen Mind, with the first 5 spells of the Water domain.
Prereq: Watery Body

Watery Form:
As earthen form, but water elementals.
Prereq: Watery Mind

Mastery of Water
you get the picture

Air Secret Chain
Knowledge: A bonus to jump checks equal to his class level, and the ability to speak Auran.
Body: The character's body is less substantial. Physical attacks suffer a miss chance equal to 5% per two class levels of the character.
Mind, Form, and Mastery are self-explanatory.

Fire Secret Chain
Knowledge: A bonus to Knowledge checks equal to class level, and the ability to speak Ignan.
Body: The character gains fire resistance 10 + his class level, and a +2 insight bonus to AC.
Mind, Form, and Mastery, yadda yadda yadda.

Wood Element

The Manual of the Planes has wood element creatures, but no wood elementals, so here goes:

Knowledge of Wood:
A bonus to climb equal to his class level, the ability to speak sylvan and treant, and an empathic link with plants within a hundred feet.

Plant Body:
The character gains a natural armor bonus equal to half his character level.

Plant Mind:
Use the first 5 spells from the plant domain.

Wooden Form:
Treat this as the druid's ability to wild shape into any plant-creature up to one size larger than the character. I would allow an extrapolated large treant from the MM huge treant for this, too, so:

Size Large
Speed 30
AC mods: +10 natural, -1 size, +0 dex
Space/reach: 10'/10'
Str 21, Dex 10, Con 17
AC bonus +10 natural.
Large size confers a -1 to attack and AC, but hey, you're a large, high-level monk, what do you care?
They keep the ex abilities, right, so double damage against objects, trample 1d8+5, DR 10/slashing, and fire vulnerability.

Then Mastery of Wood would allow 3/day shapeshifting, into plant creatures up to two size categories larger than base, and the benefits from gaining native outsider status.

OK, that's the prestige class. I like them really customizeable. With this, you could go for entry level into all five elements, or focus all the way up. I'd allow further secrets in the chains for epic creatures, which would basically allow bigger sizes for the elemental form, and maybe plane-shifting to the ethereal plane, your mastered plane, and back to your plane of origin.