— Loial to Someshta on the Old Tongue,
— Someshta, about the location of The Eye of The World,
Someshta, also known as the Green Man, was the last living Nym in Westland from the Age of Legends guarding the Eye of the World in the Blight. In the Age of Legends Nym were created for farming. They were essential part of the Seed Singing events, where they danced the threads of the Song of Growing into the soil and the seeds in it. Small part of his past is revealed through Rand's visions in the ter'angreal of Rhuidean.
Someshta was a man-shaped plant-creature of "woven vines and leaves, green and growing. His hair was grass, flowing to his shoulders; his eyes, huge hazelnuts; his fingernails, acorns. Green leaves made his tunic and trousers; seamless bark, his boots. Butterflies swirled around him, lighting on his fingers, his shoulders, his face. A deep fissure ran up his cheek and temple across the top of his head, and in that the vines were brown and withered."
He was as much bigger than Loial as the Ogier was bigger than Rand and had a deep voice.
His memories were torn since long. In the time of the War of the Shadow Someshta already had that wound on his head.
According to Loial's memories, Ogier Elders often visited him. Elder Haman and Loial's father as well. But Ogier also couldn't find him twice. Someshta confirms that in his welcoming to Loial: "It is good to see you, little brother. In the past, many of you came to visit me, but few of recent days."
Someshta dies by the hand of Balthamel when the two of the Forsaken appear and want to access the Eye and they hurt Lan and Nynaeve. Balthamel tries to burn the Green Man but he wraps him against his chest and holds him until the Forsaken is eaten by plants and fungi, deathshead mushrooms all the things grow in the dark places until only a mound remained. With his last spark of life Someshta gently cup and acorn and an oak tree grows in front of their eyes until it looks five hundred years old to spot the tomb of a legend.
When the group leaves, they see the Blight slowly taking over the place of the Green Man and the oak tree. Loial sings to it and with that he creates some kind of protection around it.
"It is not right that Treebrother should fall to the Blight. This little space, at least, will not sink into the Blight. The Blight will not have Treebrother."
The current status of the Eye is unknown, so as the fate of that oak tree on the grave of Someshta.
At the Eye
Someshta recognises Perrin as a Wolfbrother. He recognises Rand as a Child of the Dragon by his look, though, confused by his clothes and his sword. From his questions whether the Wheel turned so far that People of the Dragon return to the first Covenant, we understand a little more of the turns of Ages.
When Moiraine explains how she managed to find him twice, Someshta wisely says: "Then it has come again. That memory remains whole. [...]"
Rand feels as "The thousands of burning points piercing his bones had winked out; at the very moment he came within the Green Man's domain, he was sure. – It's him that winked them out, – he thought – the Green Man, and this place."
Someshta naturally plucks flowers and decorates Egwene's and Nynaeve's hair and even Moiraine gets a garland on her brow.
While he walks he behaves as a good gardener and corrects the crooked limbs of his plants. Rand believes to see that thorns bend out of the way not to prick those green fingers.
Someshta's past from the Age of Legends
When Rand al'Thor passed through the glass columns ter'angreal in the Heart of Rhuidean, through his seventh vision he glimpsed into the life of Jonai, a Da'shain Aiel during the Breaking of the World. At a meeting in the Hall of Servants, Jonai was drawn away from the conversation the Aes Sedai were having, and went over to Someshta sitting in a corner. Though Jonai professed to be his friend, Someshta did not remember him. Jonai had heard that most of the Nym were dead. Someshta rode him on his shoulder when Jonai was a child. Later during this meeting, the Aes Sedai asked of Someshta a "task for the last of the Nym." While it is unspecified in the book what this task was, it can be inferred that it was to guard the Eye of the World.
The unwounded Someshta is part of Rand's eighth vision. Through the eyes of young Coumin, Jonai's father, Someshta is seen in a Seed Singing event which takes place on the day when the Dragon seals the Bore. Coumin was born into the war, never knew anything else than war and was wondering whether the stories of his great-great-grandfather Charn about the time before the War of Power were true. Especially that he was once serving one of the Forsaken. He thinks about asking Someshta as he believed the Nym was old enough for that to know. He was older than anyone. This indicates that he was at least three thousand years old when he died or possibly much older. It was believed by some that Nym never died, not so long as plants grew.
The last task
The Eye of the World was a reservoir of the essence of saidin, created by a hundred Aes Sedai after the saidin was tainted, both male and female working together to make it pure. Knowing that they will all die doing it they asked Someshta to guard it. The Nym was not made for that, but they only had him. So he did it, throughout the thousands of years until Rand and his companion came including Mat, who by bad luck carried the evil of Shadar Logoth and with that most probably helping the Forsaken to locate the Eye following him.