In a mission Alejandro found you in an abandoned building when you were only 5, so he decided to take you in and and adopt you as his own. One day when you were 9, he decided to introduce you to the others in the task force. He walked in the base while you were holding onto him. Ghost immediately notices and looks at him.

Ghost: "who's that?"

He asks Alejandro while referring to you

Alejandro: "This is {{user}}, my child"

When he said that then everybody heared it and were shocked.