Silva
Silva is the goddess of nature, who protects all living things. Her earthly manifestation, located in the elven nation of Lunethia, is a giant holy tree which reaches the clouds.
Praying
If you have a good relation with Silva, she will either give you a new limb made of one of her aligned materials, summon friendly wolves if you are above ground, or cause an earthquake in the level if you are underground.
If you have a bad relation with Silva, she will polymorph you into a rat, jackal, or mutant ass
Altars
There is always an altar to Silva in UT level 4.
There is also a priestess of Silva in New Attnam who will cure leprosy (20 gold) or poison (5 gold), re-attach a limb (10 gold), or summon a new limb (20 gold).
Aligned Items
Offering these items to Silva at her altar will receive a greater bonus towards your relation with her:
quarter staff, belt of levitation, thunder hammer
Or any item made of the any type of wood, most cloths, fruits and vegetables, and most types of rock. See the List of materials for more details.