I don't want to hate but the system isn't very good for the human rankings if they're element decided there rank. end of the day it's your novel but that's very confusing
First the ranks are confusing just because someone awakens the fire element he's an S rank, second you are limiting the elements where are the ice, shadow, lightning, lava, light and darkness.
This system is so confusing to me because I'm more used to ranks being used like how they are in adventurer guilds in many novels, where it's a ranking system for how strong people are instead of being used to refer to a type of elemental affinity.