The dark faction were better suited to run the universe...
It was a notion that all light faction monarchs wanted to vehemently deny, yet somewhere deep down inside them they knew that the notion of 'might makes right' wasn't wrong at all.
Those who stood at the pinnacle of the light faction knew very well that they could get away with transgressions that a common man could never hope to get-away with.
The light faction society was supposed to be fair, but it was tilted in favour of the wealthy and the powerful with nepotism running deep within the faction.
The children of wealthy merchants were better suited to go-on and become wealthy merchants themselves despite their own competence/ incompetence whereas the poor had difficulty breaking past the middle-income threshold.
This wasn't the case in the dark faction, however, as there, anyone could become anything as long as their fists had the power to back up their ambitions.