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.

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.

Chemos–Isstvan III–Terra–Skalathrax is his graph with Fulgrim and Tarvitz: the homeworld that polished him, the betrayal drops he botched into legend, the Siege concert halls, and the ice-war where Emperor’s Children and World Eaters learned how loud a broken Legion can get.