Power.
A concept so profound, so varied, that its meaning changes based on who you asked. The power of choice; the power of many; the power of love; the power of wealth—it can go on without end.
But, the greatest undeniable power to beings who cultivate was strength. The strength to destroy, to suppress, to traverse the world freely, to claim lives, to decide your own terms in life, to pursue freedom, to grasp love, to provide, to protect loved ones, to do EVERYTHING. In the eyes of cultivators who seek the next stage of cultivation, their personal desires might be varied, profound, or vile, but the concept of power was this.
So, why did cultivators seek power? Seek out strength?