The Espers
Final Fantasy VI had an array of what were called Espers. These magic creatures as a race, created a huge element of the story. Each Esper did not have an individual story but as summons in the combat system they were a part of the gameplay and story. A few notable Espers with story elements were present. Maduin was discussed above. There is a large list of Espers. The following are two that had small parts in the story itself.
Read more about this topic: Characters Of Final Fantasy VI