I wouldn't call it moral ambiguity usually, more that it pushes the idea that previous mistakes don't define a character totally. It's basically the typical TTRPG character tragic backstory. Some of them are more greedy than others, but it's usually just that they did something wrong in the past and are trying to make up for it, or they're a different person now, or whatever. It is strange there's not a single normal character in the party though. I'd love to have some person there who's just wondering Wtf is wrong with all these people.