About the cultivation of his power, when that ethereal voice in the Dream Immortal Sleep Stone spoke, it mentioned that it was also tied to the counting of fate and the heart of heaven. The former, Tan Shuchang, had yet to feel any impact from, but he believed he had come in contact with the latter several times already.
As his own cultivation grew deeper, his communion with the heaven and earth also became more frequent. The environment included the four seasons of spring, summer, autumn, and winter along with weather phenomena like wind, rain, thunder, lightning, ice, and extreme heat. At Tan Shuchang's level of cultivation, his power had already reached the point where it could alter an area's environment.
For example, he could change the scene of the vernal equinox into the scorching heat of summer.
Of course, such a change did not come without a cost, not only did it require his own power to withstand it, but his own lifespan needed to be able to endure it as well.