Flawed Legacy
From Halopedia, the Halo wiki
Flawed Legacy is a song included in the Halo 2 Original Soundtrack.
It begins with a chorus and a slow beat of maracas. After a dozen or so seconds (around 0:16 seconds), an electric bass begins. Then, at around 0:32 seconds, an irregular drum beat mixes in and remains for the rest of the piece. This song plays like this until about 1:34 seconds, when the chorus and electric sound dies off, but the drumming and background music plays on until the end of the song. In-game it can be heard during the level Arbiter.
It is a remake of Perchance to Dream from the Halo: Original Soundtrack.