The Columba: Officia expansion adds six cards that feature characters with special powers to the Columba base game. During set-up, players randomly pick one character each in a three- or four-player game and two each in a two-player game. The remaining character cards stay on the table, and they can be acquired later in the game for the price of two "domesticated pigeon" tiles. You can steal characters from opponents for the same price, so keep an eye out for who will help you and hurt them!