(SPOILER)Reddas, as a Judge was ordered to go to Nabudis to take their shard of the large crystal thing on Pharos that the Dynast king cut loose so long ago. They got the shard and played with it I am assuming like Ghis does with the shard from the Tomb. Much like Ghis, they blew up the town there at nabudis or otherwise basically destroyed/cursed it. Reddas left the Empire then and went to Balfonheim. This was 2-3 years before the game starts you off. A little before the invasion into Dalmasca and the events at Nalbina. Reddas feels responsible for the trajedy there and mentions it many times during your interactions with him.

Major plot spoilers. That was my take from the story.. but I could have forgotten parts or not been paying attention.