Eidolon

Eidolon is Lord Commander of the Emperor's Children, loud, gilded, and already monstrous before the Laer temple finished the paperwork. He failed Fulgrim more than once and rose anyway, which is the Legion's promotion logic in miniature. Chemos made him beautiful. The Kakophoni made him a concert.

He sneered at line officers like Saul Tarvitz, led the drops that were supposed to make Isstvan III tidy, and spent the Siege turning Terra into an orchestra pit. Skalathrax heard him. So did every later warband that needed a screaming aristocrat to hold a pitch.

In the Long War he is still Lord Commander Primus, still convinced volume is virtue. The worst concerts have his name on the bill. He would take that as a review.