Attellus Zaldaki. Scum. Noble born.
He started out as a con man. Born and learned in the spires of Hive Sibellus, he threw away much of his family honor by running off on a get-rich scheme involving supposed archaeotech. Four years and thousands of thrones later he limped back, ashamed. His family accepted him only provisionally. He was blood, but they had plenty of heirs. The next few years were toil and diplomacy with the only defining point being his attempted con of a another noble. The noble was an inquisitor. And the rest, perhaps, is history.
He's changed alot since then. Where once he was a coward, now he is brave. Where once he was prissy, now he gives as hard as he gets. And where once he was scum, now he is a hero.
But it took a few years of gameplay and more than one close call to reach that. In a game with over six PCs, he is one of the final two originals. All others have fallen, failed, or fled. His survival isn't due to a stat advantage, nor due to luck. Its most often to good roleplaying, well made plans no longer than two sentences, and the partnership with the other survivor that has overcome all challenges.
But my favorite part about him is -why- he fights. He certainly worships the Emperor, but that doesn't drive him. He might enjoy his work and its rewards, but he knows it can only end one way. And it certainly isn't to build his family's name, as they are (recently) a shattered relic of a legacy he can no longer have.
He fights because the Imperium is his playground. His status, wealth, reputation, and friends he can do without. But if the Imperium falls, he has nowhere to thrive. So he -must- fight to protect it, if only to protect himself.