(Capcom's primary storyline)
"I am the National Security Advisor. It's my job to prevent terrorist attacks, not cause them..."
— Simmons, refuting accusations of supporting terrorism
The Family and Ada Wong
"How could she leave me? We were the perfect partners! She was beautiful, intelligent, and the only one I would allow at my side. She should have known that!!!"
— Simmons' note regarding Ada's departure 
Derek C. Simmons was born into a secretly historically important family. An ancestor of the Simmons line had been a founder of a secret organization known only as The Family. This organization dedicated itself to controlling the world by working behind the scenes and manipulating governments, carving out their own wishes for the development of the human race and world powers. As a descendant of the founder, Derek eventually came into power as the head of The Family, giving him limitless resources at his disposal. At some point prior to the Raccoon City Incident, Derek C. Simmons met the highly skilled spy, Ada Wong.
As the head of The Family and a high-ranking government official, Simmons provided Ada with missions that she carried out with extreme efficiency. Her intelligence and her skill won Simmons over and he eventually became more and more infatuated with her. His unrequited feelings aside, the work relationship between the two did not last. As the major hand in the sterilization operation, it was Simmons behind the complete destruction of Raccoon City in 1998. With Raccoon City having been a key point for Simmons' research in the prospective usage of bioweapons throughout the world, Simmons had obtained all of the information he needed from the incident and thus acted quickly to see to it that all evidence of the truth with the Umbrella Corporation and the U.S. government's involvement was destroyed. Pushing the administration to destroy the city, Simmons' extreme decision did not sit well for Ada. The act provoked Ada to leave his company, breaking off all contact. Ada's actions drove Simmons mad, pushing him over the edge and driving him to do something most unthinkable - kidnap thousands of women and attempt to create his own Ada Wong for his own purposes.
Carla Radames and Project Ada
The young and extremely intelligent Carla Radames came into employment under Simmons after her extensive research in genetics. While Simmons simply wanted to use her to develop viruses and bio-organic weapons, Carla had become infatuated with him just as he had with Ada. Wishing nothing more than to please Simmons and obtain his praise, Carla worked diligently to develop what would eventually become the C-Virus. As its mutative properties became more known and it was discovered they could be guided, Derek was finally able to begin the process he had promised to accomplish when Ada had left his employment. Project Ada began under the direct supervision of Carla Radames, with the goal of perfectly recreating Ada Wong.
However, disappointment ran rampant with the project, as thousands of test subjects only resulted in repeated failures and some awful monstrosities. It was not until their 12,235th experiment that there was a success. After having discovered that Carla's genetic make-up would provide the closest result, Simmons took advantage of the woman's feelings for him. He convinced her, against her better judgment, to be the next test subject. Much to Simmons' delight, he was able to witness the birth of Ada Wong as Carla was hatched from the chrysalid a decade after having started his selfish ambitions.
With Ada Wong in his life once again, Simmons dedicated himself to "programming" her. He had to make sure that she was like Ada in every regard. That was except for one thing - he had to make sure Ada would never leave him again. Everything went just as Simmons had hoped as the new Ada exhibited the same intelligence and mannerisms as the woman he remembered, though this one loved him implicitly. While Simmons was completely unaware his new Ada was beginning to have internal conflicts with the small bit of Carla Radames that remained in her very being, he showered her with her own responsibility by giving her a submarine base and complete control of The Family's East Asia soldiers. Unknown to Simmons, Carla's true persona resurfaced; angry with what he did to her, she set out to undo everything he believed in.
Agent Sherry Birkin
"Her overly-kind and ultimately naive, charitable nature makes me sick. But, she could still be of some use."
— Simmons speaking about Sherry in a note after she was given agent status
While Sherry Birkin remained in protective custody with the government, Derek C. Simmons was made her legal guardian. For unknown reasons - believed to be compassion - Derek allowed civilian Claire Redfield to visit Sherry whenever she wished, as he had seen how much Sherry felt for Claire. Unbeknownst to Simmons, however, Claire was suspect of him and had even tried to warn Sherry at one point, however Claire's letter never arrived. Claire's suspicions about Simmons were ultimately confirmed when Simmons and Carla ended up using a strain of Sherry's G-virus variant without her knowledge for further development in the C-Virus.
By 2009, the same year Project Ada had finally succeeded, Sherry Birkin was made a seemingly spontaneous offer after experimentation had finished with her and the only known threat to her, infamous bioterrorist Albert Wesker, was dead. Sherry would be made a government agent and would report directly to Simmons, providing her with the opportunity to finally have some semblance of freedom after eleven years of government custody, while aiding against the very bioweapons that caused so much damage over a decade before. Simmons realized how much he could inevitably benefit from a skilled agent with regenerative capabilities able to do his bidding, despite how he felt about her benevolent personality.
Global Bioterror Attacks 2012-2013
"My dearest Ada Wong... Jake Muller has been located in the Republic of Edonia. Your mission is to find out if his body has antibodies to the C-Virus. We cannot allow a vaccine to be produced. Agent Birkin will be sent in to acquire the target. Your job is to ensure they escape the country alive. Good luck."
— Simmons' mission to Carla Radames
By 2012, issues began to arise for Simmons. The first came in the form of the mercenary Jake Muller, the son of the deceased Albert Wesker. Simmons was informed about Jake's confirmed existence and how he was operating as a mercenary in Edonia, the birthplace of his mother. Considering the viral resistance of Jake's father, Simmons believed that Muller would have the same abilities and realized that the antibodies in his DNA could result in a possible vaccine for the C-Virus he had become so reliant on. As it was determined, Jake's blood could also be used to variably enhance the C-Virus. In a twofold step to prevent any possibility of a vaccine for the C-Virus and making it more potent, he sent his two most trusted sources to handle the situation. He sent DSO agent Sherry Birkin to take Jake Muller into custody and escort him personally to Simmons. At the same time, he sent Carla Radames into Edonia to confirm that Jake indeed carried antibodies to the C-Virus as well as to make sure that Sherry and Jake successfully made it out of the country alive and safely. However, Simmons had not anticipated betrayal and both Sherry and Jake were ultimately taken by a B.O.W. that was made in secret when his Ada Wong realized the truth of what happened to Carla Radames. Once Ustanak successfully subdued both targets, Simmons was informed by Carla that the two had gone missing and were likely killed in an explosion that had occurred. It was unknown to Simmons at the time that both had been secretly transported to China so that Carla could begin work on enhancing the C-Virus on her own.
"Now he has made an enemy of The Family and there is no turning back. It's time I use my position to make sure balance is kept in this world."
— Simmons' memo, referencing Benford's refusal to listen to his warnings
Nearly six months after the failure in Edonia, Simmons had decided to take action against the United States President, Adam Benford. Benford had planned to reveal to the American people the truth behind the Raccoon City Incident and the government's involvement with bio-organic weapons. Simmons had become perturbed by Adam's insistence and repeatedly tried to persuade him to refrain from revealing the truth, as this revelation made public would only damage the reputation of the United States and do harm to The Family's plans of stability for the country. However even with pressure from The Family, President Benford was unfazed. Thus, Derek Simmons put into motion a plan that would cause the death of the president and countless innocents. Lepotica, creatures that were capable of dispersing a gas that would cause a C-Virus infection and mutate those infected into zombies, were strategically placed prior to hatching all around Tall Oaks. However, a key component in the plan was United States Secret Service agent, Helena Harper. Simmons had Helena's younger sister, Deborah Harper, kidnapped and used the young girl as motivation for Helena to follow his demands. Caring deeply for her sister's well-being, and unaware that Deborah had already been sentenced to death by Simmons, Helena aided in the attack when Benford was visiting the campus of Ivy University in Tall Oaks, where he was to give his speech. Reporting a false alert over the agency radio channel, Helena provided an opening that left the president vulnerable, causing him to ultimately fall victim to the blue fog that engulfed the town and turned almost the entire population into zombies.
The plan could not have gone any better as Helena's attempts at pinning the blame on Simmons were easily scoffed off with his high-ranking position. Furthermore, the involvement of Adam Benford's close, personal friend, DSO agent Leon Kennedy, gave Simmons another scapegoat for the crime of the president's assassination. Now in control, Simmons put the Sterilization Operation into motion again with the intent of destroy Tall Oaks and any evidence against his involvement in the process. Simmons received a call from someone he hadn't heard from in a decade - the real Ada Wong. Ada revealed to him that Carla was hellbent on bringing down the global political order, all for petty revenge for ruining her life. Simmons left for his private jet to head to China to confront Carla, receiving yet another unexpected call; Sherry Birkin and Jake Muller were still alive, having been experimented on by Neo-Umbrella for the last half-year.
Believing the situation to be taken care of in Tall Oaks, Simmons set up a personal rendezvous for Sherry and made way for China to confront this situation. Albeit after his departure he was aware that U.S. agents Leon and Helena were following him - despite F.O.S. coordinator Ingrid Hannigan putting forth a false report of their deaths - he had made sure to provide orders to have them disposed of so they were no longer a concern. Unfortunately, the delight of the situation in America was ruined by something he had never considered - a bio-terror attack had occurred in China utilizing the C-Virus. Simmons could see his world crumbling around him as a terrorist organization calling themselves Neo Umbrella took credit for the attack.
Mutation and Death
"He had to be stopped! He was leading my country, and this world, into complete chaos! That woman, how dare she do this to me!"
— Simmons to Leon and Helena, on why he orchestrated Benford's death and frustrated about Carla's betrayal.
Still reeling from the realization that Ada Wong had betrayed him for a second time, Simmons made way to the Kwun Leng building in Koocheng - where he had set up the meeting with Sherry Birkin. Much to his surprise, Leon Kennedy and Helena Harper were still alive and confronted him and the soldiers from The Family he had with him. Only moments later, Sherry and Jake joined the meeting and it was then that Simmons finally admitted his hand in the assassination of the president. Ordering his men to kill Leon and Helena, while sparing Sherry and Jake as he still had use for them, Simmons was suddenly assaulted by a stray J'avo, one of Carla's personal soldiers. The J'avo only managed a single shot before Simmons' men killed him, but this single shot had come from a needle gun loaded with a syringe of Carla's newly engineered enhanced C-Virus. Enraged beyond all reason by this betrayal, Simmons attempted to make his escape, stumbling onto a passing train with Leon and Helena in tow behind him.
He was contacted by Carla shortly after as she relished in what she had done to him and done to the stability he and The Family had fought so hard for so long to maintain. Noticing Leon and Helena still attempting to either capture or kill him, his anger only increased at the thought that they would rather pursue him - someone who, as he felt, was trying to do what was right for his country - as opposed to at true terrorist like "Ada Wong." He then revealed his motivations for killing Benford but Helena retorted that he caused one disaster to avert a possible one at the cost of innocent lives. Succumbing to his infection as the enhanced C-Virus consumed his body, his entire structure began to split and fracture until his body ultimately mutated into a horrific monstrosity resembling a quadruped. Simmons proceeded to battle both agents aboard the speeding train, believing himself to have the upper hand with his new mutation. However, the two managed to eventually wear him down until he reached a point of vulnerability, particularly under the realization that The Family intended to leave him to die and simply replace him. He attacked in a final attempt to kill Leon and Helena, but a single well-placed shot from Agent Harper caused him to lose his balance and fall under the train. The two abandoned the derailed train cars, leaping into the nearby ocean as they believed Simmons to be finished.
However, the severe infection from the potent virus made Simmons incredibly resilient, and he survived his injuries. Although his spirit was deeply damaged, Simmons made his way to the Quad Tower where Project Ada had begun so many years ago. It was there that he confronted Leon and Helena, having already killed the BSAA agents guarding the building, and letting the zombies inside to infect the survivors. As an added surprise, the real Ada Wong made her presence known in a helicopter to provide aid for the two agents. Believing her to be Carla, Simmons accused her of taking Jake Muller away. Simmons' mutation overtook his body again, this time mutating him into a massive behemoth resembling a theropod dinosaur. Completely consumed by only the most basic of instincts - to hunt - Simmons attempted to kill the three, even throwing the weight of his body at Ada's helicopter to destroy it, as well as destroying a BSAA truck and killing its driver when he tried to aid them. Derek's body painfully reverted to its human form several times throughout the battle as he sustained more damage until he finally collapsed in his mutated body, succumbing to his wounds once more. Ada made her escape as Leon and Helena followed her up to the roof of the Quad Tower.
Death had still not taken Simmons and his desire for revenge drove him on as he stalked Ada up through the Quad Tower building. Reverting to his first mutation, he confronted the real Ada Wong personally on a connector between two of the towers. She was able to fend him off for a time, Leon and Helena managing to briefly provide aid from a distance. Frustrated with the distraction, Simmons shifted his sights to the two new targets and proceeded to attack them as they attempted to climb up the cable wire to one of the elevators. Ada returned the favor of the two agents and provided cover-fire for them, preventing Simmons from reaching them while at the same time drawing his attention back to her. Eventually gaining the advantage, Derek managed to knock Ada unconscious briefly. Leon finally managed to make his way over to the platform, protecting Ada from Simmons until she came to. Simmons did his best to prove his love for Ada and dispose of the unworthy man that was Leon, but the persistent agent continued to fight until Ada could join alongside of him. By that point, Simmons had descended so far into his own mania that his entire existence was consumed in trying to destroy Leon - the man that stood in the way of his love - and make Ada his own. The battle continued and Simmons once held an edge above his enemies despite the abuse his mutated form took. Toppling Leon to the edge of the platform, he taunted the man as Leon held on for his life. Simmons stepped on his hand, attempting to make him lose his grip and fall to his death until Ada came up behind him. Plunging one of her crossbow arrows into his torso, Ada fell off the edge with Derek. Letting him go to fall to his demise in the flames below, Ada used her grappling gun to save herself.
Simmons continued his attempt on Leon's life, surviving Ada's attempts at killing him. He followed Leon and Helena to the roof of the Quad Tower where his new mutation allowed him to absorb the living corpses created by the C-Virus gas to regenerate damage he had sustained. His first attack was short-lived as Leon and Helena managed to weaken him to the point where a small swarm of zombies that had surrounded them began to feast upon his mutated body. Simmons took advantage of this, absorbing the zombies. Newly mutated for the final time, Simmons made another attack in his massive form resembling a strange combination of different insects. He tried to dislodge a tram cart Leon rode, but was unsuccessful until he cornered the two agents just outside the heliport. Battle ensued and seemed like it would go on until his prey was exhausted as he continued to regenerate any damage sustained by devouring surrounding zombies. However, a lightning rod that had broken loose during Ada's landing scenario came into play and the agents managed to trick Simmons into devouring a zombie with the rod impaled through its body. As Simmons regenerated part of his damaged head, the lightning rod became embedded in it after he had devoured it, drawing in a massive lightning strike from the storm overhead. In the moment of freedom, Leon and Helena reached the helicopter Ada left for them to escape in until Simmons made his final attack attempt. A rocket launcher left as a gift, as well, was fired at Simmons by Leon, dislodging him from the roof of the tower and sending him plummeting below.
Simmons fell against the walkways, breaking apart, and leaving his broken human form clawing in defiance. As the separated flesh combusted, Simmons was impaled upon the obelisk in the courtyard at the center of the tower where he had confronted them earlier. Derek tried futilely to mutate again, but lacked the strength as the wound sustained slowly bled him out until he finally succumbed to death, his blood flooding the courtyard's floor, ironically forming the logo of the Umbrella Corporation, symbolizing that his actions were just as evil as Umbrella's as well as symbolizing the US government's connections to Umbrella.
Afterwards, Leon and Helena discovered a data chip left behind in the helicopter by Ada that contained the evidence they needed to clear their names and prove Simmons' guilt.
- Capcom. Resident Evil 6. (Capcom Co., Ltd.). File: Derek C. Simmons.
- Capcom. Resident Evil 6. (Capcom Co., Ltd.). Scene: To China. Level/area: Leon Chapter 3.
- Capcom. Resident Evil 6. (Capcom Co., Ltd.). File: Ada and Derek.
- Capcom. Resident Evil 6. (Capcom Co., Ltd.). File: The Family.
- Capcom. Resident Evil 6. (Capcom Co., Ltd.). File: Tall Oaks Cathedral and the Underground Lab.
- Capcom. Resident Evil 6. (Capcom Co., Ltd.). File: Two Ada Wongs.
- Capcom. Resident Evil 6. (Capcom Co., Ltd.). File: Submarine.
- Capcom. Resident Evil 6. (Capcom Co., Ltd.). File: Life without Freedom.
- Capcom. Resident Evil 6. (Capcom Co., Ltd.). File: Carla Radames (file).
- Capcom. Resident Evil 6. (Capcom Co., Ltd.). File: A Deal with the United States.
- Capcom. Resident Evil 6. (Capcom Co., Ltd.). File: Report on Jake Muller.
- Capcom. Resident Evil 6. (Capcom Co., Ltd.). File: Ada Wong.
- Capcom. Resident Evil 6. (Capcom Co., Ltd.). File: Helena's Crime.