Shialla claims to be the sister of the Tree Ghost (the collective spirit of the High Forest) and limits her influence to that region. Within the High Forest she is considered a lesser power. She is unknown beyond its boundaries save for a small temple in Silverymoon. Shiallia has been known to bestow acorns of desire on favored worshippers, which grant them the powers of a limited of full wish.

Shiallia's priest can wear any non-metal armor and use wooden shields. They may use only bludgeoning weapons and daggers. A priest of Shiallia's standard selection of spells includes major access to the spheres of All, Animal, Charm, Divination, Healing, Plant, Protection, and Weather, with minor access to Combat, Creation, Guardian, Necromantic, and Sun.

Priest of Shiallia receive 120 character points to spend on skills and abilities from the following list. Skills cost 5 to 15 points. Any unspent points can be used to acquire nonweapon proficiencies or saved for use during the game. The standard priest of Shiallia spends his character points to acquire the abilities of communicate with creatures, identify, pass without trace, shapechange, and access to spheres.

Access to spheres: The standard spell selection cost 90 character points or he can purchase spheres individually just as clerics do (see page 57 of the Skills and Powers book).
Bonus Spell (5): Once per day the priest can cast an animal friendship spell. This is a bonus spell and does not count against the priest's spell total for the day.
Cold resistance (5): +2 saving throw bonus vs. cold or ice based attacks.
Communicate with creatures (10): The priest can acquire the languages of woodland creatures, at the rate of one language per level.
Identify (5): At 3rd level, the priest can accurately identify plants, animals, and clean water.
Immunity to charm (5/10): At 7th level the priest becomes immune to charm spells cast by woodland creatures. By purchasing this ability for 10 points, the priest gains this immunity immediately.
Immunity to disease (10): A priest with this ability is immune to natural diseases.
Pass without trace (5): At 3rd level, a priest with this ability can pass without trace, as per the spell, at his normal movement rate.
Purify water (5): This ability allows the priest to cast one purify food and drink spell a day in addition to the number of spells he can normally cast.
Fire/Electrical resistance (5):A +2 bonus to all saving throws vs. fire and electrical attacks.
Hide in Shadows (5): The priest can hide in shadows, as the ranger ability, in natural surroundings.
Move Silently (5): The priest can move silently, as the ranger ability, in natural surroundings.
Shapechange (10): At 7th level the priest gains the ability to shapechange into a reptile, bird, or mammal up to three times per day. The size and shape assumed by the priest can vary from that of a bullfrog or small bird to that of a black bear. The priest can assume the forms of normal creatures only. When assuming a new form, the priest is healed of 10-60% of any damage he has suffered (round down). The priest also assumes the creature's physical characteristics (armor class, movement mode and rate, ect.). The priest's clothing and one item held in each hand also become part of his new shape (these reappear when the priest resumes his bipedal form).
Warrior Hit Point Bonus (5): The priest with this ability can enjoy the benefits of a high Constitution score as if he were a fighter. for example, if the priest has a Constitution score of 18, he would gain 4 bonus hit points per level, rather than 2.
Weapon specialization (15): The priest can specialize in a particular weapon. The character point cost must be met in addition.