The Buddha talked about karma and retribution, the cycle of life and death. If a person goes through three lives and dies due to the same regret in each life, his resentment will appear in the "Book of the Underworld" at the end of the third life, and the law of the underworld will fulfill his unfulfilled wishes. If it cannot be achieved within one month, the grudges of three generations will condense, turn into human form, and wander away from the world, but still forget why they exist in the world, and just feed on hatred day after day...