Arithir was a Ranger of the North, living in the northern kingdom of Arnor during the Third Age. He was among those who went to the foreign lands to gather informations about the Free Peoples enemies.When Aragorn came to Mirkwood on his hunt for Gollum he had a chance meeting with Arithir whom he had never before met in person, as Arithir had already been out on his wanderings for many years.