Julius Kaesoron

Julius Kaesoron was First Captain of the Emperor's Children, a noble's son who chased Fulgrim's idea of perfection until Isstvan gave him a different religion. He butchered Iron Hands in the dropsite and took trophies off men who had been brothers an hour earlier, then discovered noise could be a weapon if you stopped pretending it was music.

Santor found him already wrong: Kakophoni where a first captain used to be, screaming through the massacre instead of commanding it. Slaanesh liked the conversion enough to refuse him a clean death. What crawled back out of the Eye was a daemon prince wearing the old name like jewellery.

Chemos raised a duellist. The Phoenician raised a courtier. The dropsite raised a Noise Marine. Ten millennia later the courtier is gone and the noise is the point. Kaesoron still answers to perfection. He just stopped meaning the same word.