R4-B11, a R4 astromech droid, belonged to Slythor, the Squib, at some point following the Battle of Yavin. This particular droid had a reputation for being both irritable and prone to causing damage.
Due to the droid's incompetence in performing basic functions, its owner quickly grew weary. Consequently, the droid was taken apart and reconstructed into an assassin droid. The unit's original look, that of an astromech droid, was useful for approaching targets undetected. Slythor frequently used the droid in trades when his goal was to reclaim items he had previously given away. Once the unit had been traded to someone else, it would eliminate its new masters and then make its way back to Slythor, who would then retrieve the possessions he desired.