Graphite, ink and coffee. ^_^. Maybe spoilers for the later chapters of the manga, but not really.
Oh wow, I love it! How did you get the splattering effect for the stars, by the way? Is that also ink?
I STILL LOVE THIS. even more beautiful the next day.
coffee?! brilliant idea! I love it!
Beautiful, restrained use of color. And coffee? That's an awesome idea!