"By means of separate realities, apparently," Sirius says, his smile rather feeble as he's found the concept difficult to wrap his mind around. "Or alternate dimensions, which may or may not be the same thing, I'm really not certain."

He shrugs then, fingers still playing along the glass the of his drink. "The me he remembers is sixteen years older. I fear the day I arrived gave him a bit of a shock. To say nothing of my own reaction. I can accurately say I've had much better days in my time, which is to say, I don't blame you in the slightest for slicing open your own arm in an effort to return home."