当初遇她后来于他
[dāng chū yù tā hòu lái yú tā]
This nickname reflects a romantic and somewhat melancholic memory of past experiences. It narrates a tale of initially encountering a girl '当初遇她' and later meeting a boy/this man '后来于他'. Maybe it alludes to two important stages in this individual's life, probably indicating love stories at different periods, and these meetings left unforgettable memories on them.