Here's the last Crusader/Darkblade scene for the issue. These have been one of the tentpoles of the series, and are among my favorites to write. I just like the dynamic between Crusader and Darkblade, which is inspired by the old 70's Superman/Batman best friends relationship. I always thought putting the Man of Steel and the Dark Knight at odds was in mistake when they did it in the 80's. It looks like I wasn't the only one, either, as the friendship has come back over the last few years.
My friend Dee has pointed out that Mark drinks coffee with one of those thermal sleeve things on it (not visible in this panel). Being invulnerable, he wouldn't need one of those cardboard rings. I probably draw it that way because it's the way I drink mine, and even when the coffee gets cool enough, I still need the sleeve. There's a tactile feel to it that I've become used to. And from a visual storytelling point of view, it makes the coffee look more like coffee without saying "This is a cup of coffee."
As far as why Mark does it, I really don't know. Maybe he likes the sleeve like I do. Maybe Darkblade bought the coffee, or he bought it as Mark and tries to look like everyone else. I think I'll leave that as one of the mysteries of the series.