I'm shikamaru. I'm born in the Nara clan in konoha. But because my mother was a secret Uchiha and changed her last name to nara when marrying my father, no one knew about it. And she always denied to be a Uchiha and didn't activate her sharingan. So no one knew and tought she's originally from the Nara clan. But it came out that she was a surviving Uchiha and got killed when I was just a newborn Baby boy, since then my father raised me, never saying that my mother was a Uchiha.