Actually, your definition is incomplete.
If can mean 'out of', of 'from', but it can also mean 'after' or 'former', or 'old' or 'past' or 'no longer', which is how i thought you were using it, which is why we call former relationships "ex's"
That's actually how i was reading it, he was now 'bloodied' and an ex-hero, or 'former hero'... e.g. he murdered a prisoner and is now an ex-policeman, or in the proper mid-English vernacular, "a bloodied policeman, formerly".
Essentially a Fallen Hero.
Certainly a more classical English phrasing, but then i thought that was the point? Steampunk always speaks in higher English and not the vulgar Americanized. I assumed that was intentional.
Besides, It's a fantasy. You can modify the languages how you want, and the Ex on the end just sounds better to me. Harder edge that rolls off the tongue with a guttural X utterance at the end, rather than having to recover from guttural utterance in the middle and continue speaking. It also harkens to the Rex title for Kings, lending that regal ambiance to the title as well.