Sang Yu's birthday is February 29th
In years without February 29th, he will have his own day between February 28th and March 1st.
Sang Yu thinks this is a time and space bug, but he likes it very much
When he was about to celebrate his fifth birthday, Sang Yu left himself a wish. He gave the four wishes he had saved to Du Jinyou, and then chose to leave this world.
So no one remembers him anymore
Except Du Jinyou.
Text be warning
Intention: love yourself