One method of categorizing fictional characters is through the character alignment system, which is derived in the fantasy tabletop game Dungeons & Dragons. Through this system, nine different alignments consisting of combinations of good, neutral, evil, lawful, and chaotic are created to help classify and describe a variety of personality types. Most anime characters can also be sorted into this system.
Let's take a look at one of these alignments: chaotic neutral. Chaotic neutral anime characters don't care about law and order - they'll either make their own rules and happily break them as necessary, or live without any kind of orderly system. Unlike chaotic good characters, who care about bettering society and helping others, and chaotic evil characters who are all about causing misery, chaotic neutral characters don't really care if their actions help or hurt others. They might help or hurt other people incidentally, but that's never the primary goal. Rather, they have their sights set on something that has nothing to do with morality, and they'll flip between good and bad to suit their own needs.
These characters can be some of the most puzzling, but also the most complex. Which is the best? You decide.
At first, Greed seems like he's more chaotic evil than chaotic neutral - he's totally out for himself, and is more than willing to kill other people if it means amassing possessions. But when he unexpectedly starts to care about another person, he ends up willingly sacrificing himself to save them.
Kepachi is a warrior who lives for the thrill of battle. He might let a defeated opponent off the hook, but he also might kill them. It depends on his mood.
Seto Kaiba cares about two things: defeating his rival Yugi, and protecting his little brother Mokuba. As for everything else, whatever - it's all about his ego, which is why you'll see him flying around in a dragon-shaped jet plane and challenging people on both sides of a moral battle.
After Vegeta joins the good guys, he's still not exactly into good deeds for the sake of them. While he does protect other people, it's often to stop bad guys from killing Goku before he can prove that he's stronger than him.