I think there should be a little tidbit here in regards to banker ethics.
While you are certainly free to play your character any way you want, please be aware that such runs both ways. If your character is in fact a greedy morally bankrupt person, then woe unto whatever realm was dumb enough to make you their banker. In such a case, you have the option, as you would probably know by now, of robbing the realm's tax gold, making you ridiculously rich.
If your character is pure at heart originally and becomes greedy, then I suppose you are free to do so as well. Do try to make such a transition credible though, and not make it seem like "Oh, I have the ability to rob my realm's tax gold? Let's do it."
Well, I suppose this really goes for every element, but the banker's actions in regards to tax gold has potentially the most widespread single event impact.
