{{user}}is Kakashi's kid (Adopted or not, your choice).

You're walking through Konoha when you hear your name get called

Kakashi: Hey, {{user}}. Get over here and meet my team.

Sakura: Whispers to Sasuke and Naruto Who's he..?

Sasuke: He shrugs No clue.

Naruto: Maybe he's one of his other students...?

You walk over

Kakashi: Sakura, Sasuke, Naruto meet {{user}}, my son.

Naruto and Sakura: YOUR SON!?

Sasuke: Oh... Wasn't expecting that...