The Woodstriders are an ancient type of mage, of whom legends where whispered long before High Magic was even an idea in the head of an elvish scholar. Woodstriders are found mostly in the Borderlands of Leng, for this is where their art originated, but they can be found elsewhere, though always in wild places. It is said amongst the Woodstriders that the Way cannot be taught, though this is not entirely true. The truth is that the Way of the Woodstriders is not a skill to be taught so much as a part of all creatures that must be unlocked. In a way, it is the same part that enables druids to wield the power that they do, the part of the being that connects them to Nature, to the lifeblood of all beings. But the Woodstriders do not gain their abilities by acting as shepherds, protecting and balancing nature. If anything, they are the wolves and sheep, part of Nature, and they gain their abilities by becoming wilder than any mortal has a right to be, by unlocking that part of them that is primal and animalistic.
The power that this grants is the ability to take on the form of animals. To begin with, a Woodstrider will only be able to assume one form, and then with great difficulty. The form they take will usually be one that reflects their personality; this first form is the most powerfully entrenched within them, and is the one that feels most comfortable, like an old comfortable shirt. As they grow into the Way changing forms only becomes easier, and most eventually master two, three, four or more forms, each of which they may assume at will. Unsurprisingly, Woodstriders are almost always rangers, though some are fighters or thieves.
However, this power is not without danger. It can be intoxicating smelling with the nose of a wolf or flying with the wings of a bird, for it is not only the form that is being taken, but the memories, the instincts, the very essence of being the wolf or the crow or the bear or the fish. The more time one spends shifted, the more one takes on the characteristics of the animal. For many Woodstriders, the joy of changing shape is so great that they will spend days at a time in their favourite form, then weeks, then months. Eventually they will stop changing back - maybe they have forgotten, maybe they simply no longer wish to be a human. Eventually, they stop thinking with a human mind entirely and simply become the animal. All Woodstriders are warned to be careful and guard themselves, lest the intoxication of shifting cause them to lose their own identity.
A shapeshifter draws their power from the same source as a Druid, though they control and interact with it in very different ways. The shapeshifter kit can be applied to any class except a Druid (if applied to the Ranger class, they gain no Druid spells). Applying the kit does not affect the base class in any way except to increase the experience threshold of each level by 20% (so if 2000 experience would normally be required, it becomes 2400). Wearing metal armor of any kind disrupts a shapeshifter's ability to transform for 1 hour after it has been removed. All shapeshifters gain the ability to communicate with any animals they can take the form of, even when in their natural shape.
From 1st level, a shapeshifter gains the ability to take on a single animal form. This form follows the same guidelines as the Druid's shapechanging ability; the animal in question may be a reptile, bird or animal. It must be common in the shapeshifter's territory, and can range from a creature the size of a bullfrog to one the size of a large bear. The shapeshifter selects a single animal to take the form of, and may not change into any other creature. The shapeshifter cannot use items or cast spells while transformed, and takes on all the properties of an average specimen of the creature in question. The shapeshifter may change between human and animal forms as often as he desires. Shapeshifters always use the average hit die of the creature whose form they assume. A transformed shapeshifter uses either their own THAC0 or that of their new form, whichever is better.
Each time a shapeshifter gains a level, they have a chance of gaining a new form. This is a percentage change with a base value equal to twice the shapeshifter's wisdom. Depending on how true to their instincts and bestial nature the shapeshifter acts, the DM may apply a bonus/penalty between -20% and +20% to this chance. If the result is below 0%, the shapeshifter will lose access to one of their forms (most recently acquired forms are lost first). A shapeshifter cannot lose their last form unless -10 or lower is rolled; in this case, they will lose all abilities of transformation and will lose the potential to assume any new forms, though their higher experience thresholds will remain as a consequence of ignoring the instinctive nature that they have unlocked within themselves. Amongst Woodstriders - particularly those of differing traditions - the number of forms that one is able to assume is a mark of rank and seniority.
Once a shapeshifter attains 12th level, it becomes possible to acquire a lycanthropic form. A shapeshifter may never have access to more than one lycanthropic form. Finally, the choice of lycanthrope is restricted; if the shapeshifter has access to any forms that correlate to a lycanthrope, they must choose that type - for example, if they have the power to assume the form of a bat, they must become a werebat. If they have more than one form that has a lycanthropic variant, they must choose the older (and thus more comfortable) form. If none of their forms has a lycanthropic equivalent, they may freely choose from the forms that are reasonable and well-represented in their area. A shapeshifter from the woods of Leng could not opt to become a werepanther, for example, as they are found only in Kyujitai. As with their other forms, the lycanthropic form can be assumed at-will.
Upon changing to a lycanthrope, the shapeshifter gains the natural AC, immunity to nomagical weapons, THAC0, hit dice and natural attacks of the creature in question. Their strength is also increased to 19 while in this form. Shapeshifters with a lycanthropic form are considered to be true lycanthropes for all intents and purposes, meaning that they retain their presence of mind when shifted. If their natural HP is better than that of their lycanthropic form, they retain it while shapechanged, and they do likewise with THAC0. As with other natural forms, shapeshifters cannot cast spells while shapeshifted, but they may use weapons if they have them. Shapeshifters are only able to assume the hybrid form of the lycanthrope in question; they do not gain the animal form as a freebie. It is still possible for a shapeshifted lycanthrope to transmit the curse of lycanthropy through their natural attacks, though less likely; a mere 1% chance for each successful hit.
Once a shapeshifter has fallen and lost their power to transform, the only way to restore their abilities is to return to their home territory and train under the care of a shapeshifter of their clan/tribe/pack. After each month of training, the character must make a wisdom check. If they succeed, they regain the ability to change into their first form. If training with their original brethren is impossible., they must find a Woodstrider of some other clan/tribe/pack to take them in and agree to train them. Due to the xenophobic nature of most Woodstriders, this is very difficult; even if accepted, training under a foreign master will also take twice as long (one wisdom check every two months). It should be noted that most Woodstriders consider losing one's shapechanging abilities to be a mark of ultimate shame.
Although shapechanging frequently is obviously key to gaining access to more forms, shapeshifters should be mindful of that balance that must be struck between their human and bestial halves. Spending more than three hours a day in an alternate form is dangerous, and making a regular habit of this will cause a shapeshifter to regress, degenerating into a more bestial form. While to begin with the changes will be entirely IC from a game perspective, with time the effects can become even more drastic. When the DM judges it appropriate, a shapeshifter will enter Minor Regression.
Minor Regression has the following effect on the shapeshifter: each time they change form, they must make a saving throw vs. polymorph at a +6 bonus. If they fail, they are trapped in their current form until they next sleep, upon which they will return to their natural shape. Each time this happens, the bonus is reduced by 1, to a minimum of a -4 penalty. If they fail with the -4 penalty, they progress to Major Regression.
Major Regression carries with it the same effects as Minor Regression, though the penalty does not worsen past -4. In addition, each time they sleep there is a 1% chance that they will assume one of their forms (usually the one they are most comfortable with) unconsciously, waking up and behaving as an unintelligent animal of that kind would while the sapient mind sleeps. Each time this happens, the chance of this happening in future increases by 1%. When it reaches 100%, they are lost, completely assuming the form in question and becoming no more than a dumb beast. This is totally irreversible - even a Wish can do no more than restore them to human form and reduce the chance back down to 90%.
Once regression has begun, the easiest way to reverse it is to rest and avoid shapechanging. If the shapeshifter continues to adventure and advance in experience while doing this, it's entirely possible they'll have a lower chance of gaining a new form when they level up; in the long run, it is better to maintain a balance between man and beast than to give in completely. When resting and recuperating in this way, human contact and interaction will speed their recovery. Training with a master Woodstrider and/or meditating will also help speed their recovery.