The First Noise Marine by ~NickNightshade
(Description from the DA page this was on)
"This is Marius Vairosean, Third Captain of the Emperor’s Children during the Great Crusade. Beyond his considerable status in the Emperor’s Children Space Marine Legion he is significant because he is credited as being the first Noise Marine. These hedonistic monstrosities are so jaded that they must constantly surround themselves with chaos and noise to experience any sensation.
His tragic story is one of the dangers of ambition and the pursuit of unattainable perfection. Marius’s fall began during the Cleansing of Laer when his Third Company warriors failed to reach the objective in accordance with the Primarch Fulgrim’s masterfully planned assault. The Emperor’s Children strive for perfection above all things, and Marius’s perceived failure drove him into a self-destructive depression and a fanatical desire to redeem himself. This led to him volunteering for numerous experimental surgeries and procedures engineered to make himself a more perfect warrior. Instead it rewired his enhanced nervous system until nothing but the most extreme stimuli could elicit any emotion from him.
This disciplined, honorable Space Marine completed his fall as he witnessed the demoniacally-enhanced opera The Maraviglia. The corrupting influence of the song-ritual combined with his mutated physique led him to become the first Noise Marine, and when he was seen again slaughtering loyalist Astartes on Istvaan IV wrapped in human skins he was armed with the weapon-instruments of the Maraviglia, his mouth permanently ratcheted open so that he could never stop screaming in sadistic pleasure.”