First off, the quote is, "For the love of money is the root of all sorts of evil." So taking credits to kill a man isn't evi... um.
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Secondly, our game doesn't really have the concept of "neutral" when it comes to the Light/Dark. Additionally, I'm of the mindset that Light/Dark affiliation isn't something you simply state and then are. Bounty Hunters, while working for the highest bidder, do things that are morally ambiguous at best, and morally reprehensible at worst.
PERSONAL OPINION INCOMING: I believe that within the Star Wars universe every known character can be classified as Light or Dark, and that BEING one of these two things doesn't mean that you're "Good" or "Evil". In the same way a person can be fundamentally "Dark" and yet still do "good" things (Asajj helping Ahsoka), someone can be "Light" and be on the path of "evil" (Anakin, duh). I mean, look at Anakin, was he EVER really light side? Sure he's done a lot of good things, and his affection for Ahsoka is truly pure and fatherly, but his actions are through-and-through driven by a fundamental selfishness.
Sure, he's "Light Side", but that doesn't mean he's a good guy.
In the same way, Bounty Hunters are Dark Side in that they have willingly chosen a profession that is inherently morally "dark". While some of them can be "decent" individuals, and even "good" in some aspects of their character, they have willingly chosen a "dark" path. Thus, they are unlikely to be flagged as Neutral and will remain Dark Side (unless we get indicators that a character should be flagged otherwise).
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