Thorald Greenhand is known in Rohan as a gardener of some skill. He has a keen mind in herb-lore and an odd obsession with trees. He is often found dancing in the woods and plays sweet tunes on his flute that carry along with the wind. He leaves a faint sweet scent of flowers and honey in his wake.

He is kindhearted and takes great delight in the cooking and sharing of hearty meals, taking a particular liking to blueberry jam and full-bodied red wine. Whenever he returns from the woods, he brings with him sweet fruit and whole baskets of sweet root, which he hands out to the children.

He is quite a simple man who does not concern himself with the troubles of the world, save the wellbeing of tree and woodland stream. He often leaves his home for great lengths of time, sojourning in the many woods of Middle-Earth. He has been seen in serious conversation with trees, which has led some to believe that he is but a crazy old man. His choice of attire, which is oddly coloured and decorated with leaves and flowers, does not help to persuade otherwise.

But in truth, Thorald is a lesser Maia of Aulë and Yavanna named Calmatan, Lampwright, summoned from Valinor by Yavanna and tasked with safeguarding the olvar of Arda and finding the Enyd and their wives so they may prosper once more. He awoke first in the shape of a great tree, as one of the Enyd, and walked many years in tender earth tasting fresh mountain springs. When at last he took on the shape of a man, he had nigh forgotten the purpose of his coming. So slow he was now in thought and speech that it only added to the believe that he was a gardener of simple mind, and because of it the Rohirrim heed him little.