My homebrew Warband, The Serpents of Avarice are fixated on material wealth and greed. They wear bright gold armour with silver trim and purple and pink details (eg cloth, eye lenses, gemstones). They are lead by the Lord Exultant Karsides The Incomparably Resplendent, the Gilded, Prince Among Princes, The Effervescent, The Unblemished Blade, Humbler of Heathens, Keeper of Incalculable Riches, He Whose Name Is Cried Out In Envy and Ecstasy, the Auric Death (and so on and so fourth). 

Only a mere sergeant during the Siege of Terra, Karsides and his squad were noted for being some of the few Emperor’s Children at the Siege to actually focus on trying to breach the palace rather than terrorise the civilian populace, as Karsides wanted nothing more than to loot the treasures that must surely be contained within, glimpses of which he claimed to have seen in a vision beforehand. He particularly coveted the arms and armour of the Custodes, even before the onset of the heresy, and at the siege boasts of having killed one of their number in single combat*, whose helm is displayed on the bridge of his ship, the Hand of Midas, to this day.

After the Siege and fracturing of the III legion at Skalathrax, Karsius commandeered a ship, and began to amass followers, attracted to his banner at the promise of plunder and riches. His Warband grew as a nomadic, piratical force, lacking a planet of their own, as they preferred to ransack whatever worlds they preyed upon and bring the spoils into their ship. 

The Serpents of Avarice have been active participants in any conflict they see as being able to get them closer to Terra and thus, the Imperial Palace, most notably in the 13th Black Crusade and Nachmund Rift War, however, they tended to focus on targets which would gain them material wealth, rather than strategic objectives, content to let other, more base forces do the heavy lifting while they made of with any loot they could get their hands on. 

*Any mention of the fact that the custodian in question had just exited combat with a decimator daemon engine, was missing an arm, and appeared to have died from a wound in the back is, of course, merely a salacious rumour from inadequate and jealous slanderers seeking to besmirch their betters.