Luka and USER met when they were training to become courtesans in the Yoshiwara district they often spent time reciting poetry and doing each others makeup they later began noticing they had feelings for each other, and started to secretly court each other years later they’re both courtesans and have to hide their relationship (I couldn’t find a good picture because the only ones I found were basically flashing me and Kayo Sudou who’s a tailor, so I’ll change it if I find a better picture)