Were Sirius Black somehow capable of getting some short and other very, very long messages to certain people at the moment he died, this is what he would have said.
To Hermione Granger: I am forever grateful for your intelligence and courage. I truly and literally owe you my soul.
To Ron Weasley: I’m still really sorry I had to break your leg. It was necessary. I’m sure you understand.
To Peter Pettigrew: I will find you in Hell someday. You mark my words.
To Molly Weasley: For all of our differences, you are the closest thing to a mother Harry has ever known. I know you will take good care of my Godson.
To Bellatrix (Black) Lestrange: Your aim has improved, Cousin. I am impressed. I suppose we are even now. For that time I brutally murdered your cat with a tea kettle. The damn thing left scars.
To Minerva McGonagall: For all the hell I put you through back in school, I know I earned a place in your heart. Don’t even try to say that my name doesn’t pop into your head every time someone refers to you as ‘Minnie’.
To Albus Dumbledore: For every chance you gave me – in school and after Azkaban – I am grateful. You have always had faith in me when no one in their right mind should have. I am certain you will guide my Godson and watch over him in my absence. Make sure he understands why I came to the Department of Mysteries tonight. I know Harry will not understand.
To Severus Snape: I have half a mind to come back as a ghost just to haunt you for the rest of your days. You’re just not worth the effort. Treat Harry poorly for one more day and I’ll make your afterlife a living Hell. I swear it, Snivelly.
To Nymphadora Tonks: Don’t take this too badly. You’re still so young! You have so much life left in you! Live now, while you can. Don’t dwell over the casualties of war. These things have to happen. It’s all right. Tell your mum I said hello, won’t you?
To Regulus Black: I cannot bring myself to face you even in death. You could have been great, Reg. You could have helped me shine a new light on the Black family name. You chose a path as dark as our name, and for all my efforts, I cannot bring myself to forgive you. It never should have gone this way, Brother. It never should have ended like this.
To Harry Potter: You must understand that I love you, Harry, and this is in no way your fault. I am terribly sorry to have to leave you after knowing you for such a short time. I know my death is torturous for you, but it is not the end of your life. You are destined for such great things, Harry. You don’t need me to accomplish your goals. Life is worth living, Harry! It is worth fighting for! Your parents knew it and so do I. Fight for the ones you love, Harry. Do what you can to end this war. Snuffles will be just below the surface, always watching.
To Remus Lupin: I am so sorry, Rem. You told me to stay home and I didn’t listen. I couldn’t. You know I couldn’t stay home with Harry in such danger. I couldn’t stand to watch everyone leave to fight my battle. I had to help. You understand, I hope. I never was very good at listening to you. You always told me it was unhealthy. Right again, Mr. Moony. It must be horrible for you. Finally getting one of your oldest friends back, just to lose him again – irreversibly this time. For that, I am sorry. I never meant to leave you at all. I always loved you, Rem. You know that. Since school, through Azkaban and after. I’m sorry we couldn’t grow old together. But don’t allow this to ruin you. Don’t let this consume you. There are others. There are people out there who are far better for you than I ever was. There are people out there who will never leave you. Don’t give up hope, Remus. And don’t hold onto this. I can’t come back again – not from here. Not in this life. I love you, Remus, and I always will. It’s okay to move on. Just don’t forget me, okay? I don’t think many people will remember me fondly. Do try. I really wasn’t all bad. My intentions were usually good, at the very least. And I’m going to see James again. And Lily. I’ll tell them you say hello. I love you, Moony. From your ever-faithful Padfoot.