Basic Trope: A seemingly evil character turns out to be hard to clearly categorize anywhere on the good-evil continuum.
Straight: Antonio works knowingly for the Big Bad, puts effort into inconveniencing the heroes, and never seems to have a problem with actions of his boss. Despite this, he never really does anything truly evil himself.
Exaggerated: Antonio fights alongside bad guys without looking the slightest bit bothered about this. He constantly sabotages the heroes' efforts, covertly manipulates situations to his advantage, and plays mind games with everyone. However, he also refrains from doing anything outright heinous if he can, is ready to hop to good guys' side (at least for a while) if the tide seems to be turning and can seriously claim noble motives.
Downplayed: Antonio is villainous at first sight, although he seems to hold back for some weird reason.
Winning the trust of the villains is the quickest and the most effective way for Antonio to advance his own goals.
Enforced: "Grey and Gray Morality is all the rage these days, we should get rid of some of Antonio's more heinous acts, so he can remain ambiguous."
Lampshaded: "You know guys, for a villain, he doesn't seem all that bad."
Invoked: "As long as I don't do anything truly evil, I can fight for whatever side I want, and the heroes won't have an excuse to get rid of me."
The Hero knows that Antonio will most likely not do anything too hasty against him and his team, so he starts playing mind games on Antonio.
Even though Antonio's working with the Space Nazis, the heroes know that he's sufficiently uninterested in the ideology for them to just bribe him into supplying the heroes with Space Nazi secrets.
Defied: "If I'm a villain, then I might as well go all the way! Now, where's an orphanage that I can burn down?"
Discussed: "Is he really evil, or is he just messing with us?"
Conversed: "These, 'are they good or bad,' type of villains always wind up having the most amount of fans, I tell you."
Deconstructed: Antonio's refusal to commit alienates both sides. The villains can't trust that he won't sell them out, and the heroes are suspicious of his ethics. As a result, Antonio frequently finds himself fighting both sides, and is unable to accomplish any of his own goals.