One of the EV-series droids to have installed a MDF motivator to improve its efficiency, the MDF also provided them with malice and torture skill. MerenData tried to cover the incident and, when it was discovered, they tried to recall all of the droids. EV-4D9 was not recovered.
EV-4D9's master did notice the droid's brutal tendency and even promoted it. With a few modifications, the master had an effective interrogator. EV-4D9 was provided with an arc welder, a plasteel cutter, a thermal drill and three different solution injectors for truth- or pain-inducing serum.
During the Glite-Ven hostilities, EV-4D9 was noticed by Lotas and HN-TR1 of Ploovo's Protocol Team. Both of them expressed their interest on EV-4D9 and Ploovo Two-For-One, following their suggestion, acquired EV-4D9. EV-4D9 since joined the Protocol Team, and Lotas repeatedly expressed admiration towards its darkly analytical functions.