One of the Rangers of Ithilien under the command of Faramir. It was he who tracked Gollum, and if he had carried out the laws, he should have slain him before reporting to Faramir and the hobbits. It is thanks to his compassion that the Quest of the Ring was able to succeed.
Reference - Lord of the Rings
Sept. 12, 2002
Anborn was a ranger of Ithilien under the command
of Faramir, Son of
Denethor. During the War of the Ring, he spotted Gollum in the
forest of Ithilien, and at first, thought it was just a black squirrel
from MIrkwood. He didn't slay him because Faramir would not have his
rangers kill wild beasts without reason.
Later, Frodo was awakened by Faramir to go and see the Moon rise over Gondor. The descriptions of the moon rising, and the views from the Window of the Sunset, Henneth Annun were very detailed, telling of views of Ered Nimrais.
From the Window, Gollum was spotted fishing in the lake below. Anborn was the one to suggest firing at him, and had Faramir given the order to shoot, the destroying of the Ring probably would have never come to pass. Anborn then led Frodo down to the lake, under Faramir's orders, so that the hobbit might persuade Gollum into coming into the Henneth Annun. It was Anborn that tied Gollum up, and lifted him up to the Window. To be a ranger of Faramir's took great skill. Anborn seemed confident in his ability to shoot the small, dark shape of Gollum at night, so most likely he was a great bowman. He was quite loyal to Faramir, and carried out all the orders given to him, even against his own judgment.
Anborn defended Ithilien when the Southrons attacked, and most likely was by Faramir's side when he recieved the black breath defending Osgiliath.