"Jin's" qi is apparently naturally aligned to growth and the element of Wood, and since they have the same body the same should likely be true of "Rou". If this is the case, it provides an additional reason why Rou's cultivation was so slow compared to Jin's, over and above the effects of the Pact of Shennong. Rou was training first in the middle of a massive city, then atop a barren mountain far above the treeline, both places where Wood qi would be scarce. Jin, on the other hand, immediately moved out to a forested wilderness, which even in the qi-poor Azure Hills would still probably be richer in wood qi. Notably, in the very first chapter Jin starts feeling better and more energetic the instant he descends into the forests on the mountainside.
