"Padfoot".

Remus stared at his own handwriting for what seemed like hours. It had been years since the death of his closest companion, Sirius Black, but he felt the urge to write him a letter—to say words that could never be read, perhaps not even by himself. He pondered how he would compose the letter if Sirius were still alive; perhaps he would tell him about Tonks's promotion at the ministry, or dedicate an entire paragraph to Teddy's first word (which was "daddy"). Taking a deep breath, he put quill to parchment and finally began his letter.

Padfoot,
I don't know who I was kidding when I married Tonks. She will never mean half of what you still mean to me. Teddy is the only possible good that could come out of this—I only hope he grows into a man braver than his father, who is not afraid to tell the person he loves how he truly feels. I miss you terribly.
Forever yours,
Moony

Tears smudged the ink as he folded the parchment up, sealing it inside an envelope. He paused momentarily to wipe his eyes before tossing his letter into the last dying ember in the fireplace.