The second kind are the "selfish." These are the people who live only for themselves, and try to get what they can from the system. You can always count on them to act in their own self-interest. They're the ones who will do something nasty behind your back if they think it'll get them a leg up. You can't ever really trust them, but you can depend on them.
Then there are the "dangerous." This is the very smallest group. These are the ones you find at the top of society, and also at the bottom. These are the kind who have no qualms about killing, if they feel like it. And that's why they can reach the top. They'll betray, backstab, and kill their way to the top. That's how they become famous, or rich, or whatever. Then when they die, they usually die young and violent.
The fourth kind are the "weak." I put these with the meek, because that's where you find most of them. The difference is that the weak know they're powerless, while the meek think they have some power. The weak have the will to fight, but no real strength. They'll get trampled. But every now and then one of the weak rises to the top and becomes the dangerous.