Emperor's Children - Earning the Palatine Aquila: It was after the Proximan Betrayal early in the Great Crusade that the IIIrd Legion was granted the exclusive right to bear the Palatine Aquila, the Emperor's personal standard, in its own heraldry, the only Space Marine Legion allowed to display the Aquila on its arms and armour until after the Horus Heresy, when the practice spread to all the Legions that had remained loyal to the Imperium.This honour was bought in blood as the IIIrd Legion's XVIth Cohort (chapter), assigned to the Imperial Compliance ceremonies and as the Emperor's honour guard for Proxima's formal accession into the Imperium, fought and died to the last warrior alongside the Legio Custodes, never giving ground during the insurrectionist surprise attack on that world's ceremonial plaza. By their sacrifice was the wounded Emperor, who had suffered injury through the use of a Vortex Weapon by the enemy, bought time to recover and fight His way clear of the Proximan insurrectionists' trap.In recognition of this, the standard of the Palatine Aquila so fiercely fought for that day was given to the Astartes of the IIIrd Legion by the Emperor's own hand, to be their relic ever after, along with the right to end the Proximan revolt by Exterminatus and so repay the blood that was owed them.While the great Aquila in its variations signified both the Imperium of Humanity and loyalty to the Emperor as its master, and there is much allegory bound up into its form, for the IIIrd Legion it also now represented their own deeds as well, an honour never given to another Space Marine Legion before the Great Betrayal.In situations of hazard and utmost danger, the Emperor often used members of the newly redubbed Emperor's Children Legion as aquilifers and equerries due to their singular character and mien, a responsibility the Legion was proud to carry. Bearing the palatine eagle standard of the Emperor, members of the IIIrd Legion accompanied Imperial diplomatic missions and emissaries as bodyguards and agents into the heart of the foe, and in battle bore the standard and commanded the armies of the newly conquered as instruments of the Emperor's will and judgment if needed.The sight of the Emperor's symbol carried by one of His favoured warriors was enough to keep many a wavering new ally or recently conquered Human world in line. These standard bearers, and the honour guards that accompanied them, symbolically coloured their armour with lacquer of traditionally imperial purple to mark their rank and mission.So arrayed, none could doubt that these Astartes were the chosen of the Emperor, and such was the record and esteem with which they functioned that for a time it became common for them to bear the Emperor's wishes and orders to other Legions and Imperial military forces scattered across the new-born Imperium.The nature of the IIIrd Legion's psychology meant that they would carry the precise meaning and intent of any order without deviation and with their last breath if needed. In this role, the IIIrd Legion took on the mandate of the Emperor's will, and no other Legion was so honoured. Others bore His words, but at this time the IIIrd Legion were His voice. This would not change, even after the Emperor's Children were reunited with their long-lost genetic forebear and primarch, Fulgrim.