Central to how you play any given match of Cantata is who your Commanding Officer (CO) is. Going beyond the simple model of an invisible, passive leader, choice manifests directly on the battlefield as a unit and can be controlled in the same way as any other unit you control.
Not only this, but every CO can have a passive effect on nearby allies or enemies, meaning that proper placement of them over the course of a battle can mean the difference between victory and defeat.
COs also affect how you actually play with any given faction, but for a little more on that I suggest you consult the Cantata Guide.
Cantata has nine COs, one for each of the game's factions, and each echoes the wider story of the game and the background of the faction in a way unique to them. Over the course of the final game, you'll play as each CO at least once, seeing the ongoing war from different angles and from different sides of the conflict.
For now, I'd like to introduce you to the first three of nine COs, one from each of the game's factions. You can click through to read their page in the guide, and feel free to ask any questions in the comments below.