Legend

From Halopedia, the Halo wiki

200px Legend is a song included in the Halo 3: Original Soundtrack. It plays during the Legendary ending cutscene of Halo 3.

It starts with a slow and peaceful woodwind melody, followed by a choir-accompanied short motif. Suddenly, a cacophony of noises erupts, and the song abruptly ends.

It runs for 0:39.