Tamm was a wise woman from the village of Nest and the mother of the sorceress Thaegan.
Tamm was well-known and liked by her neighbours in Nest for her magical healing abilities and successfully brewed love potions. She gave birth to a daughter, Thaegan, toward the end of Queen Elspeth's reign. Thaegan quickly grew bored with her mother's simple life and turned to dark magic to satisfy a hunger for power. Tamm tried to reason with her daughter and, when she failed, control her, but to no avail. She woved a shutting spell around the family's house, but Thaegan, who was far stronger in magic than her mother, broke the spell and fled into the Barrier Mountains in Deltora's north, only to return seven years later even stronger than before. It is unknown what became of Tamm after Thaegan's reappearance, however it is possible that she was eaten alive by Thaegan as her daughter's favourite food is live raven.
Thaegan went on to become one of the most feared beings in Deltora's history, second only to the Shadow Lord himself. Over a century after Thaegan's birth, Tamm was mentioned by Josef in Thaegan's section of the The Deltora Book of Monsters.
Nothing is known of Tamm's physical appearance, though she could shapeshift into a blackbird.
Tamm was a gentle, kind individual, the opposite of her daughter in nearly every way. She was exceptionally fond of animals, especially birds, and she was popular because of her magic. Thaegan broke Tamm's heart when she ran away. It is not clear why Thaegan bore so much animosity toward her mother, other than simple spite.
Tamm was a talented sorceress, though she was nowhere near as powerful as her infamous daughter. She was particularly skilled in the creation of love potions and healing spells, and was able to weave shutting spells around locations, as seen with her and Thaegan's house in the village of Nest. Tamm was famous for her ability to transform into a blackbird at will.