Crush the world beneath your heel. Destroy everyone who has ever slighted you. Tear down creation just to see if you can. Kill anything beautiful. Take what you want. Desecrate everything.
The Mirror of Erised is supposed to show your heart's desire - so why does Harry Potter see only vague, blurry darkness? Aberforth is Headmaster, Ariana is alive, Albus is in exile, and Harry must uncover his past if he's to survive his future.