The Eagle and the Mountain
"The Eagle and the Mountain" was first published in Astro City Special: Samaritan.
Time-travelling alchemist-turned super-villain Infidel and super-powered super-hero Samaritan realize that they are both evenly matched, and that it is a waste of their time and efforts to fight one another as they realize the other can always undo what they do. Therefore, they agree to stop fighting and instead each host one meeting a year at a location of their choice. This year, Infidel realizes that they are both slowly wearing down the other, much like the Eagle in the legend of the Eagle and the Mountain.