Arien is the Maia who guides the Sun in J.R.R. Tolkien’s legendarium.
In Tolkien’s mythology, Arien is a spirit associated with fire who becomes the driver and guide of the Sun. She is described in The Silmarillion as having been chosen for this task because she was not harmed by the heat of the Sun. Her role begins after the destruction of the Two Trees of Valinor, when the Valar establish the Sun and Moon.
Arien is not one of the Valar, the greater divine powers of the world. She belongs to the Maiar, a lesser order of immortal spirits that also includes figures such as Gandalf, Saruman, and Sauron. Arien’s work is therefore part of the cosmic structure of Tolkien’s early mythology rather than the central plot of The Hobbit.
She is sometimes confused with Tilion, the Maia who guides the Moon. Tolkien’s account gives Arien the Sun and Tilion the Moon, creating the paired celestial journeys that shape the passage of day and night.