Gwindeth is found inside a cave, Gwindethrond, the entrance of which is situated behind the waterfall in Rushingdale near Lake Evendim. She also appears within Haudh Elendil and the Flooded Ward during two quest instances.
She was an adviser to the Kings of Arnor and has lived for many centuries. Her exact nature is unclear; her connection to Lake Nenuial points to her being a water-spirit similar to the River-maids but her temper is more stern; it is also possible that she is a Maia who decided to remain at the Middle-earth. These two theories are not mutually exclusive.
- "What brings you to this place?"
- "I am the caretaker of Nenuial. Do not disturb its peace!"
- "I was a friend to the kings of old. Can you say that?"
- "Deep within the folded lands along the shores of Nenuial, known to most as Lake Evendim, lies a grotto, its entrance hidden behind a waterfall – but this is no ordinary cave, for it is home to Gwindeth, the Blue Lady of Evendim. Who or what she is remains a mystery, but she has dwelt at Gwindethrond for many an age, and was a friend to the Kings of Arnor, from Elendil to Amlaith of Fornost, the first King of Arthedain. Some believe she is kin to the River-maidens – though her temperament is much stronger than theirs – or perhaps even one of the messengers of the Valar who chose long ago to remain in Middle-earth.
- "At the behest of Amlaith, Gwindeth placed under her protection the last of the Silithair, gems of surpassing beauty and power crafted by the Elves. Aragorn, son of Arathorn, came to Gwindethrond to seek the Silithar, but Gwindeth turned him aside. Aragorn still hopes that the Silithar can be recovered, for its power will be needed to help drive back the Shadow in the East." — lorebook