This is great. The sense of nostalgia and what-ifs and may-bes in the wake of what we--and in many ways, Regulus--know what's going happen sets the tone. I love all the details of Regulus' childhood and all his reflections on Sirius. Even though there's no resolution between Reg and Sirius, there's one of sorts here, in this moment, and it's enough to burn at the corners of my eyes.

Great job.