Marty O'Donnell (aka Marty, the Elder, username KPaul) is the Audio Director at Bungie. He has written the music for Myth, Oni, and both Halo games. In both Halo 1 and Halo 2, he is the voice for Jackals, Hunters and Flood.
He has worked closely with Michael Salvatori to produce music for the Halo Games, and the two coproduced the Halo: Original Soundtrack and Halo 2: Original Soundtrack together.
Marty's sound studio is called the "Ivory Towers", which is very similar to the name of a multiplayer map in Halo 2, Ivory Tower. In addition, this tower is noted to be owned by a character named Lance O'Donnell.
Before working for Bungie, he did audio work for several TV/radio commercials including Flinstone Vitamins. He was once co-owner of TotalAudio, a company that produced sound design on Riven.
He is currently the arch enemy of Frank O'Connor. Ironically, Martin usually does the Bungie weekly update when Frankie is unable to.