J.R.R. Tolkien invented the Ents as the shepherds of trees.
The Ents appear most prominently in The Lord of the Rings. They are ancient, tree-like beings who guard and care for forests. Their name comes from the Old English word ent, meaning “giant,” which Tolkien encountered in the phrase eotenas ond ylfe from the poem Beowulf.
Treebeard, or Fangorn, is the best-known Ent. He leads the Ents and Huorns against Isengard after learning how Saruman’s Orcs have destroyed trees. The assault destroys much of Saruman’s stronghold and demonstrates the power of a forest acting under its own ancient guardians.
Ents are not identical to Huorns. Tolkien presents Huorns as tree-like beings closely related to Ents, but more mysterious and less communicative. The Entwives are another distinct group, associated with gardens and agriculture; they disappear before the events of The Lord of the Rings, leaving the Ents searching for them.