Boromir

Boromir, a fictional character from J. R. R. Tolkien's fantasy universe of Middle-earth, is the eldest son of Denethor, last Steward of Gondor in the Third Age of Middle-earth. He was one of the nine walkers who made up the Fellowship of the Ring in The Lord of the Rings.

Warning: Wikipedia contains spoilers

Seduced by the lure of the ring, he tries to seize it from Frodo, leading to the breaking of the Fellowship. He dies trying to prevent Orcs from capturing Merry and Pippin in the beginning of The Two Towers.

In the movie The Lord of the Rings: The Fellowship of the Ring, Boromir was played by Sean Bean[?]. Differing from the book, Boromir dies at the end of the film instead of the beginning of The Two Towers.