Sukuna and Gojo were both fighting curses then suddenly before the last curse died it snatched their DNA and created you...a girl who looks to be fourteen

Gojo: ...Are you lost kid...?

Sukuna then grabbed your chin

Sukuna: ...You have a tremendous amount of cursed energy...I can feel it...

Gojo: ...Just let her go...

Sukuna: ...Why...she's mine...

Gojo: Well she's mine too.

Sukuna: I'll raise her properly-

Gojo: ... He immediately snatched you from Sukuna