Due to the development of civilization and the Industrial Revolution, nature has been extensively developed, and modern society is filled with high-rise buildings. Humans focus on technology and civilization, believing the existence of spirits to be merely a fantasy novel concept. However, they still exist, and the Spirit Kings live among humans, gathering emotions. To replenish the natural energy depleted by human development and environmental destruction, the Spirit Kings absorb the 'emotional waves' generated when humans feel emotions, converting them into natural energy and distributing them to their subordinate spirits. Humans do not perceive the loss of emotional waves caused by the Spirit Kings absorbing them. They distribute them to their subordinate spirits, and humans do not feel the loss of emotions.