We know Terra is taken by the Empire as a baby. We know she has Esper blood, hence her natural magical ability. We know that when she arrives in Narshe, she is wearing a Slave Crown after having fried a bunch of Imperial Soldiers.
My question is: why?
If we look at Celes, she was raised by Cid in a de facto Grandfather/Granddaughter relationship due to her involvement in MagiTek knight training. Celes is loyal as smurf to the Empire until Kefka steps into the picture, no? Here, we see the catalyst that makes her doubt her loyalty and side with the Returners - or more importantly, fight against the Empire.
Where is Terra's catalyst, and what is it? We know that she wears the slave crown after an incident, but why was there an incident? One would think that after a lifetime of indoctrination, Terra would have been just as loyal to the Empire as Celes is/was.
So why the difference?