Don't Meddle With My Daughter/Nightmare Fuel


 * While a lot of villains are, to some greater or lesser extent Played For Laughs, Heavy Metal is one of the few exceptions. In fact, he's one of the few villains the plot does not try in any way to diminish his seriousness a bit. The reason is sickening: He purposely set out to rape Athena, simply in an attempt to break her spirit and force to live with the horror of being the mother to his children. He fails miserably, but the plot not only regards his evil with all horror it deserves, it's revealed that while Athena has shrugged off other similar acts, that one was so scarring she still has nightmares about it.
 * Once you find out WHY went to the dark side, you cannot fail to completely understand and sympathize. She was a genuinely heroic person, but she was viciously subjected to both Mind Rape and the more literal version multiple times to the point she was willing to do anything to make it stop.
 * The are also one of the few times the plot stops trying to be remotely funny and explicitly acknowledges what they did in an attempt to create an army of Super Soldiers as unrepentantly evil. It's implied their fates after their crimes were exposed were not so pleasant, but honestly, those vile animals had it coming, especially after they tried to throw the very heroes they wanted to defend them under the bus just to save their own worthless skins for the mess THEY created. In fact, the plot in general would have never happened had these monsters never existed.