At the start of the Clone Wars the EX unit was nothing but a minor project of Aelund, a lead scientist of the CIS. EX units were designed to be infiltration units, built to go behind enemy lines and cause chaos. The first couple dozen field tests were complete disasters and as such the EX program was put aside.

Much later in the war a group of clone commandos launched an attack on the research base headed by Aelund, as the Republic had learned that the CIS were conducting some top secret experiments there. The attack failed, leaving all of the commandos except one, RC-277 also known as Havok, dead. He was captured and used by Aelund to further two of his projects. The first being the use of organics as an interface to better train and program droids. The second was the resurrection of the EX program, and thus EX-66 was created. EX-66 was encased in Havok's armor, and then "plugged" into his brain after Aelund had completed the necessary- and traumatizing- surgical procedures on Havok. What followed was the slow and agonizing download of Havok's experience and training into EX-66, after which various battle simulations were run using Havok's brain as the simulator.

During one such simulation an explosion rocked the research base, knocking out both the regular and emergency power generators. This caused EX to be locked into Commando Mode, temporarily causing himself to believe that he was Havok, and sabotage the facility while attempting to kill Aelund in revenge for what he had done. Aelund managed to escape when EX's main personality retook control.

Having been designed to be autonomous while in Commando Mode, he left the now destroyed base and traveled the galaxy, focused on the last objective in his memory bank, hunt Aelund down. After all this time EX has managed to track Aelund to the Sluis Sector, having spent the last of his credits getting there.

Ambition: Power- To find Aelund and after dispatching him use his research to create an advanced droid army under his control.

Bounty (+25) or Bounty (+20)- CIS lead scientist has put a bounty on EX-66, wanted mostly functional, in order to continue using him in experiments and eliminate him as a threat.