WARSHAPER

Most martial characters rely on manufactured gear such as the sword or shield to survive on the battlefield. Even those of a more technical persuasion rely on technique of civilized design. The Warshaper scoffs at these limitations, preferring instead to rely on the brutality of nature, unmatched for millions of years.
Capable of suddenly transforming their bodies in the blink of an eye, rearranging their vital points to negate damage, and suddenly expanding their existing weapons to phenomenal size. It's not until the soldier you're fighting suddenly sprouts fangs and tentacles that you know you're fighting a warshaper.

REQUIREMENTS:

BAB: +4.
Special: Must be able to change shape, whether by Shapechanger subtype, Polymorph as a spell or SLA, Wild Shape or similar class feature, or Change Shape supernatural ability.
The alternate form ability (quasits, vampires, etc.) is not sufficient to qualify as a Warshaper.

BAB progression: 2/3.
Fort Save: Good.
Reflex Save: Poor.
Will Save: Poor.
HD: d10.
Class Skills: Same as one base class user possesses.
Skill Ranks per level: 4+INT mod.
Weapon and Armor proficiency: Warshapers gain no additional weapon or armor proficiencies.

Morphic Immunity (Ex): At 1st level, the Warshaper becomes adept at distributing her form's vital organs around her body to keep them safe from harm, becoming immune to stunning and critical hits.
Morphic Weapons (Su): At 1st level, as a move action, the Warshaper can grow natural weapons such as claws or fangs, allowing a natural attack that deals the appropriate amount of damage according to the size of the new form. These need not be natural weapons the creature already posseses. If the Warshaper's current form already has a natural weapon, the warshaper can instead use that move action to cause the weapon to deal damage as if it were one size category larger - for example, a Warshaper currently in the form of a Dire Wolf (Large) could grow its jaw and snout, enabling a bite attack that deals 2d6 points of damage (as if for a Huge animal) instead of the normal 1d8. A Warshaper can change morphic weapons as often as it likes, even if they are currently accessing their form using an ability that normally doesn't allow any further changes after the initial transformation, such as Wild Shape.
Morphic Body (Su): At 2nd level, the Warshaper's precise control of their form makes them stronger and heartier. The Warshaper gains +4 Strength and +4 Constitution.
Morphic Reach (Su): At 3rd level, the Warshaper gains the ability to suddenly stretch its limbs, neck, or other appendages, giving them an additional 5 feet of reach. Unlike most creatures, Warshapers don't appear to have a longer reach until they actually use it.
Morphic Healing (Su): At 4th level, the Warshaper's control over its body improves such that they can manipulate away wounds that appear, creating smooth skin over bloodied gashes. The Warshaper gains fast healing 2, and may spend a full-round action to make a Fortitude save with a DC equal to the total damage sustained (or, Max HP-Current HP); on a success, the Warshaper heals 10 points of damage.
Flashmorph/Multimorph/Diremorph (Su): At 5th level, the Warshaper gains one of a number of abilities, based on how they change shape.
If the Warshaper can change form at will, such as from the change shape ability, the shapechanger subtype, or a polymorph SLA, it gains the flashmorph class feature, alowing it to change form as a move action.
If it casts the polymorph spell, has a polymorph SLA that cannot be used at will, or has the wildshape class feature, it instead gains the multimorph class feature, allowing the Warshaper to change forms multiple times during the duration of the spell, SLA, or ability. Each change requires a standard action, only the first transformation heals the warshaper, and if the Warshaper returns to their natural form, the spell, SLA, or ability ends.
If the Warshaper can only change into one form and transforms as a move action or less, it instead gains the Direform ability. For every 5 character levels the Warshaper possesses, they select one creature template from the following list: Acid, Cold, Diamond, Dire, Fire, Half-Dragon, Mythical Animal, Negative Energy-Charged, Positive Energy-Charged, Electric. When the Warshaper transforms, they choose one template they know and apply it to the transformed form. If their transformation would give the Warshaper attribute bonuses, those bonuses are superceded by the template bonuses if they are higher.