NWars:Commanding Officers

Commanding Officers are the Nintendo Wars characters in charge of their respective armies. While they actually have no gameplay role and vary from map to map in Famicom Wars, and aren't around in the Game Boy Wars series (despite the presensce of a superior in Game Boy Wars 3), in Super Famicom Wars and the Advance Wars games, each CO affects their army's abilities.

Day-To-Day is the CO abilities that take effect daily.

Super Famicom Wars
COs can be selected for a match or a single-player file. On a single-player file, COs can't be changed at any point, including inbetween maps. Human player and 4-player matches are unaffected because they don't save anyway.

All computer-controlled COs have varied AI. Only Caroline, Billy Gates, and Yamamoto have any abilities that aren't involving AI, all Day-To-Day. All three have no weakness, and the latter two can be considered broken because of how powerful their Day-To-Day is.

The Super Famicom Wars COs have yet to make another appearance.

Advance Wars
All COs have CO Powers, and the ones who have any Day-To-Day (everybody but Andy) also each has a weakness, with the exception of Nell, who is unlocked only by beating Hard Campaign.