While the quartets are about pairings, there is still some disagreement about which are the pairs.
For example, Reddit (Matthew) pairs:
PALADIN
• Devotion (white knight) / Vengeance (black knight)
and at first that seems a strong contrast. But when going to the remaining two:
• Glory (civilization) / Ancients (wilderness)
Glory corresponds less well to civilization. The themes are Olympic athletes, individualism and body culture.
Then when returning to the description of Vengeance, it actually is about civilization.
"Vengeance is a commitment to punish those who have committed evil acts. When evil armies slaughter helpless villagers, when a tyrant defies the will of the gods, when a thieves’ guild grows too violent and powerful, when a dragon rampages through the countryside."
In other words, Vengeance is a police force. They who keep the peace of civilization.
So, while there are pairings. Some are more obvious than others. I am curious what the designers have in mind, when they pair off the subclasses.