Earendil is a character from J.R.R. Tolkien's legendarium, primarily featured in "The Silmarillion." He is a half-elven mariner who plays a crucial role in the history of Middle-earth. Earendil is known for sailing the skies in his ship, Vingilot, carrying a Silmaril, a precious jewel that contains the light of the Two Trees of Valinor. His journey leads him to the realm of the Valar, where he pleads for their assistance against the dark lord Morgoth. As a result, Earendil becomes a symbol of hope and is later transformed into a star, guiding and inspiring those in Middle-earth.