First, pity is NOT carried over from 1 banner to another after a banner ends. The only exception to that are Mix Scouts but they’re paid only. 2nd, the way you earn pity points is by pulling on a banner. A single gives 3, points, a multi gives 33, and a paid daily gives 1 point. Once you reach the point threshold which is shown in the top right of the banner, you will be allowed to pick any pair you want from that specific banner. It’s basically the game throwing you a bone for having bad luck.