Tobal Siy was an Imperial commander, who was in charge of the Star Destroyer Thunder. He was often tasked with tracking Rebel smugglers in his sector. This was a great challenge to Siy, as the smugglers seemed to always be a step ahead of Siy. Siy suspected that they might have placed a spy within Imperial ranks. Little did he know that the spy was his own protocol droid, N-3PO, who was in reality a Shard in disguise.