Official introduction:
The Captain is the most mysterious figure in Honkai Impact 3rd.
There is no background information and no defined abilities.
He can be such a good-for-nothing that all he can do is work as a dim-witted cleaner who does the splits high above the ground, or he can be powerful enough to wield the Judgment of Shamash without so much as a scratch.
In the Captain's Home story, the Captain's gender changes from male to female, and various clues seem to suggest that he is also someone who transmigrated.
He knows countless secrets, yet is as innocent as a total newbie.
Wait, could he also have some connection to the former members of the Dawn Squad?!!
Literary version:
Yin and yang conceived in boundless, fallen violet; writhing chaos and ineffable friendship. Eras and lives endlessly turn in cycles, while black feathers are stained with white foam...
The twin children of black and white, the white-haired guardian, the hopeful Raimei, the sickly lovestruck green lily, the quiet dream of Sakura...
I just want to be with, my love...
*I guess... this is probably a naive, amateurish story from a student who initially just wanted to write a complete setting for a silly moe story, then got so frustrated by miHoYo changing its own lore that they decided to flesh out the Captain's identity and add a few original elements...