In a twist to the usual format of the series, Deveraux serves as the main antagonist in the final entry, Day of Reckoning.

Luc's comrade, Sergeant Andrew Scott, goes insane and begins killing Vietnamese civilians and fellow American soldiers indiscriminately.

The two attempt to find the source of the Black Tower program and help Luc regain his identity, while Scott and other UniSols are sent to kill them.

Set sometime after the events of the original film,[a] the budget for the Universal Soldier program has been slashed by the government, but a CIA director known as Mentor, orders the gang of mercenaries to take control of the new line of UniSols, to use them to smuggle diamonds to the highest foreign buyer.

Veronica follows and while sneaking into the UniSol lab to rescue Luc, she discovers that his older brother Eric, a deceased soldier from Vietnam, is resurrected.

Meanwhile, CIA director Mentor and Dr. Walker are in the process of creating a powerful UniSol clone of Luc's brother, Eric, to assassinate him and Veronica.

With his partner Maggie, he is attempting to refine and perfect the UniSol program in an effort to make a new, stronger breed of soldier – one more sophisticated, intelligent, and agile.

When SETH discovers that the UniSol program is scheduled to be shut down because of budget cuts, he defensively takes matters into his own "hands".

Luc must also contend with the ambitious reporter Erin Young, and General Radford, who wants to take extreme measures to stop SETH.

Luc then battles Romeo, who gains the upper hand but Maggie stops him, having rebelled against the UniSols following SETH's demise.

Deveraux forcibly returns to active duty by the US military to participate in a mission to rescue the Ukrainian prime minister's children, held hostage by renegade Commander Topov in the Chernobyl nuclear power plant, which is rigged with a time bomb.

Luc Deveraux has been on the run from the military ever since the day he left the Chernobyl nuclear power plant and his hair is shaved off.

He enlists another clone of Andrew Scott, his former nemesis, to recruit other wayward UniSols, thus establishing a violent cult aiming at a new world order.

Instead, Deveraux frees John from government control and hires him to perform tasks for his separatist organization, such as assassinating key members of the new UniSol program and shipping stolen high tech equipment to his bunker.

John II finally kills Deveraux and takes over his organization, motivated by the grudge he harbors for the US government that caused his pain.

In the Universal Soldier film series, the character of Devereaux undergoes significant development and exhibits various traits.

After breaking free, he displays curiosity and confusion about the world, showing a lack of social graces and childlike interest in many things.

In Universal Soldier: Regeneration, Devereaux is portrayed as a partially human and UniSol hybrid, depicting a broken man haunted by a past he barely remembers.

[2] In Universal Soldier: Day of Reckoning, Devereaux's weariness and fatalism are evident as he accepts his lack of humanity.

Regeneration implies that full rehabilitation is extremely difficult, if not impossible; though Devereaux makes considerable progress in the area of emotion, it is almost too easy for him to fall back into the relentless UniSol mentality.