In the video game Middle Earth: Shadow of War, the protagonist Talion ends up disturbing the Spirit of Carnan, an Ent-like being who controls & defends her section of forest. Given that the Ents lost the Entwives long ago, and have even forgotten what they look like... could Carnan be one of the missing Entwives?
According to the producer and director, he doesn't think The Spirit is an Ent-wife but that she would definitely know Entish.
She is a spirit of nature. She could be a Maiar. I don’t think she is an Ent-wife, but I think she probably knows what happened to them. She definitely would be able to speak Entish, but she is definitely a representation of the spirit of nature and what would happen to that if it was in somewhere oppressed by darkness, industry and horror as Mordor is.”
Michael de Plater during live stream
Edlothiad has given an excellent "Word of God" answer. I would like to explain why the character in the game would not be an appropriate choice for an Entwife if the game had attempted to be true to the books.
The Ents and Entwives grew apart
Treebeard tells Merry and Pippin that the Ents and Entwives grew apart because the Ents loved the great trees and the wild woods:
But the Entwives gave their minds to the lesser trees, and to the meads in the sunshine beyond the feet of the forests; and they saw the sloe in the thicket, and the wild apple and the cherry blossoming in spring, and the green herbs in the waterlands in summer, and the seeding grasses in the autumn fields. They did not desire to speak with these things; but they wished them to hear and obey what was said to them. The Entwives ordered them to grow according to their wishes, and bear leaf and fruit to their liking; for the Entwives desired order, and plenty, and peace (by which they meant that things should remain where they had set them). So the Entwives made gardens to live in.
The Lord of the Rings Book Three, Chapter 4: Treebeard
Page 475-6 (Single volume 50th Anniversary Edition)
The Entwives no longer live among trees
The Entwives became gardeners or farmers. Indeed, it seems to me that the split between the Ents and the Entwives is intended to recall the changes in human society with the birth of agriculture.
... After the Darkness was overthrown the land of the Entwives blossomed richly, and their fields were full of corn. Many men learned the crafts of the Entwives and honoured them greatly; but we were only a legend to them, a secret in the heart of the forest.
The Lord of the Rings Book Three, Chapter 4: Treebeard
Page 476 (Single volume 50th Anniversary Edition)
The Entwives no longer look like Ents
The appearance of the Entwives changed greatly, so that I don't think they would look anything like the character in the game. Treebeard says:
‘I remember it was long ago – in the time of the war between Sauron and the Men of the Sea – desire came over me to see Fimbrethil again. Very fair she was still in my eyes, when I had last seen her, though little like the Entmaiden of old. For the Entwives were bent and browned by their labour; their hair parched by the sun to the hue of ripe corn and their cheeks like red apples.
The Lord of the Rings Book Three, Chapter 4: Treebeard
Page 476 (Single volume 50th Anniversary Edition)
It says in the game appendices "like the Entwives" so I guess she's not, but close?
As far as I can tell she seems almost a parallel to yavanna, the valar of growing things. Maybe she's supposed to be a servant of yavanna? Idk. Most of my knowledge comes from the legendarium of the books and these games, as great as they are, are vastly different to the books in terms of lore
