回首已是百年后
[huí shŏu yĭ shì băi nián hòu]
This nickname expresses a sense of profound nostalgia. 'When I look back, it is already a hundred years later.' This phrase often conveys sorrow over lost time or opportunities that can never return again. It suggests that life changes so much, even to the extent that when you recall your memories one day, everything has changed completely.