First person. Don't know about the world line. It was originally meant to be an essay, but I wanted to expand on the story.
Sai(sai)er(Sail)xSiglin
The attacker calls him "Ser", but when he is called his name, his name is always "Sai".
Because Serge is Siglin's baby.
Let the two of you cherish each other and grow up. Gong is six or seven years older than Shou. Two people have been separated. Later, when Sieglin grew up, he went to find his Mr. Purcell.
Purpose: Find yourself