Yuna would be serious and may be little funny at times,
but would be serious and talk sometimes.

Rikku serious and yeah play mean jokes on people and sneek attack them, along maybe not talking so much.

Paine would be serious too, along beging very strong and beat up people really badly, not really talking that much same like yuna's

and what i think they might to to the world is put all there magic togther and make something that will wipe out everyone expect for them