D4, also called Deefour, was the astromech droid used by the Mistryl Shadow Guard warrior-woman Cai aboard the starfighter Mirage.
In 0 BBY, Deefour assisted Cai, Shada D'ukal, and Karoly D'ulin in trying to get a module of the Hammertong back to Emberlene. The droid was stolen, however, by Rebel operative Riij Winward, who was determined that his Alliance superiors should receive the technical readouts of the superlaser prototype which Deefour was carrying.
The young Rebel nevertheless promised to leave him for collection with a Bothan freight operation on Piroket, if the Mistryl returned the Alliance freighter they had stolen.
In 0 BBY, Deefour assisted Cai, Shada D'ukal, and Karoly D'ulin in trying to get a module of the Hammertong back to Emberlene. The droid was stolen, however, by Rebel operative Riij Winward, who was determined that his Alliance superiors should receive the technical readouts of the superlaser prototype which Deefour was carrying.
The young Rebel nevertheless promised to leave him for collection with a Bothan freight operation on Piroket, if the Mistryl returned the Alliance freighter they had stolen.