There's a secret in Professor Potter's office that, if you know where to knock, reveals the name of every wizard and witch who died for the cause in the Battle of Hogwarts. When Albus lingers a little too long, he pulls back the curtain.
Every name on the wall died for his father to live. He's the only one left to inherit the Potter legacy, since James and Luna went with their mother in the divorce.
And it's a legacy smeared with blood, tragedy, and high expectations.
"Sometimes I wish you weren't my son."
Albus wasn't his father's first choice.