if We Are One can be called the theme for the Astartes and\or the Primarchs, then this can be Emps's theme

epic

Helghast Vengeance

Composer: Frank Klepacki.
Release date: November 8, 2001.
Game: Command & Conquer - Red Alert 2.
Platform: PC.

Mash-Up / Re-Edit of B Mashina using various versions of the song and snippets from the movie Iron Sky - enjoy!