(Covers information from Anderson's universe)
Raccoon City Incident
Immediately following the disaster in The Hive, it was Isaacs who, at Cain's direction, experimented on Alice and Matt Addison after being pulled from the Tyrant program. But disaster struck when Cain unwisely chose to re-open the Hive, despite the containment procedures. Undead and Lickers escaped the facility, and the T-virus overran Raccoon City, with Alice and Addison, now subjects in the Nemesis program, still inside.
Following the bombing of Raccoon City, Isaacs was distraught to learn that both Alice and Addison were dead. But he was able to recover Alice's body from the wreckage of the helicopter she used to escape, and moved her and his work to an Umbrella facility in Detroit. After three weeks of experiments, Alice was revived with incredible new powers. Unfortunately, she retained her memories and escaped, being rescued by Jill Valentine, Carlos Olivera, and Lloyd Jefferson Wayne. But Isaacs had one last trick up his sleeve, and as Alice makes her escape, he activates "Project: Alice".
Experimentation on the Undead
Five years after the Global T-Virus pandemic began, Isaacs commanded the Umbrella North American Research Facility and attempted to come up with a way to combat the pandemic. To this end, Isaacs worked to track down Alice and attempted to use her clones to domesticate the Undead to create a workforce for Umbrella to retake and rebuild the world with. Isaacs experiments and rebellious nature often made him clash with Umbrella Chairman Albert Wesker and Alexander Slater.
Unable to locate Alice and with her clones repeatedly failing the tests Isaacs set up for them, he created a serum using the blood of Alice's clones to attempt to domesticate the Undead without Alice. Isaacs was able to create the Super Undead, Undead that regain their intelligence, reasoning skills and memory. However, the Super Undead also gained a much greater aggression and the first subject slaughtered the two scientists helping Isaacs test him. Despite this, Isaacs made ten unauthorized trips to the surface in 24 hours and created more Super Undead, seeing them as useful despite their heightened aggression. Isaacs also continued to clash with Slater who was disgruntled at Isaacs blatant insubordination.
After Alice intervened to stop the Undead crow attack on Claire Redfield's convoy, the White Queen alerted Isaacs to the spike in psionic activity from Alice's telekinesis as Isaacs used a Super Undead against Specimen 87 on the testing floor. Using the spike of psionic activity, Isaac was able to triangulate Alice's position, repositioning the remaining Umbrella satellites and thwarting Alice's previous ability to avoid satellite detection. Isaacs was able to get a 62% match for Alice's identity and brought it to Wesker with the suggestion that he assemble a strike team and hunt Alice down. Wesker refused the suggestion and instead chose to wait until they had a 100% identification, specifically ordering Isaacs not to act until the Umbrella Committee decided what to do.
Attack on Claire Redfield's convoy
Disobeying Wesker's orders, Isaacs used a recording of the meeting between them to falsify orders from Wesker that allowed him to go after Alice immediately. Tracking Alice towards Las Vegas, Isaacs loaded a shipping container with his Super Undead and dropped it where he knew it would block the way of Claire Redfield's convoy and force them to face the Super Undead.
Having set up a command post on a nearby rooftop, Isaacs watched the Battle of Las Vegas through Alice's eyes using an Umbrella satellite feed. Isaacs was impressed with Alice's combat ability, calling her "magnificent." Once all of the Super Undead near Alice were dead, Isaacs ordered his technician to "shut her down" which resulted in Alice being frozen in place. Isaacs then ordered his men to get a sample of Alice's blood as soon as she was dead as he needed it while it was still warm.
However, before Isaacs' men could move in, Alice began to fight the conditioning despite the Umbrella technician's efforts to boost the signal. Finally, Alice fried a chip on the satellite and broke free of the Umbrella control.
Isaacs and his men eventually gained a new satellite feed and learned that Alice was headed straight for them. Isaacs desperately ordered his technician to shut Alice down again, but she was able to keep herself from falling under Umbrella control again. Realizing that he couldn't stop Alice, Isaacs fled to his helicopter as Alice killed the soldiers in the command tent. As Isaacs boarded the helicopter, he was bitten in the shoulder by a final Super Undead. The pilot killed the Super Undead and as they returned to base, Isaacs desperately called out for the anti-virus.
Mutation and Death
Upon return to the North American Research Facility, Isaacs was placed under house arrest on the order of Alexander Slater and injected himself with massive amounts of the anti-virus in a desperate attempt to combat the more powerful T-virus infection he received from the bite of the Super Undead. Noticeably sick and losing his hair in places, Isaacs was confronted by Slater who revealed that he had been ordered by Chairman Albert Wesker to kill him. Slater shot Isaacs in the heart, but this only triggered Isaacs mutation into a monstrous creature. Isaacs killed Slater with his new tentacles and went on to slaughter everyone else in the facility. The White Queen was able to lock Isaacs in the lower levels of the facility for a time, but he would eventually be able to break out.
After Alice arrived with the survivors of Claire Redfield's convoy so they could use Isaacs helicopter to reach Alaska, she entered the facility and discovered the aftermath of Isaacs rampage. Alice was informed of the events by the White Queen who told her that she could use her blood and the facility's equipment to create a cure to the T-virus but first had to eliminate Isaacs.
In the labs in lower levels of the facility, the fully-mutated Isaacs attacked Alice, flinging her into the bubble holding another Alice clone. Alice hit Isaacs in the shoulder with a kukri, forcing Isaacs to retreat, but he quickly regenerated once the kukri was removed from his shoulder. Following the apparent death of her clone, Alice encountered Isaacs again in the mock-up of the Looking Glass House. The two engaged in battle, but Isaacs superior size, strength, regenerative and telekinetic abilities gave him the upper hand.
After a failed attempt to kill Alice with his tentacles, Isaacs telekinetically blasted her through a wall and into the facility's recreation of the Hive's laser grid. Believing himself to have won, Isaacs taunted Alice that he had believed that she was the future but that he was wrong and instead he himself is the future. Having noticed the laser grid activating behind Isaacs, Alice taunted him that "no, you're just another asshole and we're both gonna die down here." Isaacs realized too late what was about to happen and was sliced into cubed pieces by the laser grid, finally killing the deranged scientist. Alice's clone, who had revived in time to use the laser grid to kill Isaacs, deactivated the laser grid in time to save Alice's life. Watching Isaacs' body fall to pieces, Alice's clone taunted him "yeah, you're the future alright."
In The Final Chapter, Alice is shocked when she encounters what appears to be Isaacs in an Umbrella tank years after his death. Alice quickly realizes that this Isaacs was simply a clone and believes that the one she has encountered is the real Alexander Isaacs. Later, when Alice tells Claire Redfield that Isaacs is coming after them, she is shocked as she too believed Isaacs killed by Alice. Alice explains to Claire how the Isaacs she killed was just a clone.
Dr. Isaacs was a man of cool temperament, being knowledgeable and rational. After the Global T-Virus pandemic, he worked for the good of mankind under Umbrella chairman Albert Wesker, trying to locate Alice and take a sample of her blood, thus creating a more effective cure to the T-virus. His methods were unorthodox, however, and he regarded his work with a higher priority than the lives of his colleagues or a few civilians. In fact, one might go as far as to call Isaacs selfish, cowardly, and cruel.
This is evidenced by the fact that after the initial test of his serum designed to domesticate Undead failed, and the Undead went berserk, killing a scientist. Dr. Isaacs quickly slipped out of the room, locking the doors and sealing a second scientist inside. That scientist could have easily escaped, had Isaacs quickly let him slip out while the enraged Undead was preoccupied feasting on the first.
However, Isaacs coldly watched as the man was ripped apart and eaten alive by the Undead, coolly running his fingers through his hair and adjusting his tie. His instincts for self-preservation also showed itself during the ambush in Las Vegas, when Alice attacked the Umbrella tent. Isaacs quickly fled to the nearby helicopter, leaving his colleagues to die. Isaacs maintained a wary relationship with Alexander Slater, who did not much like the scientist.
- Novelization information ends here
This Isaacs clone showed no signs of the religiousness that motivated the the other Isaacs clone and the real Alexander Isaacs and that drove the other Isaacs clone insane. However, as this Isaacs didn't appear to have the memories and knowledge of the real Isaacs as the other clone did, his personality likely differed in this respect.
Powers and Abilities
After his mutation into a Tyrant, Isaacs gained powerful abilities. Notably, his wounds regenerated within seconds, only remaining open if an object was inside of them and then healing once the object was removed. This rendered Isaacs nearly invulnerable with even being blasted through a wall just stunning Isaacs for a few moments. The only known way to kill Isaacs as a result was complete destruction of his body. He also had superhuman strength and a trio of deadly tentacles with pointed ends Isaacs could use as powerful weapons. With just a roar, Isaacs was able to unleash a powerful telekinetic shockwave, which unlike Alice, caused him no pain and/or weakness.
Appearance and wardrobe
Alexander Isaacs was a tall, middle-aged Caucasian man of British background. He had sea-green eyes, and dark blonde hair. Isaacs was usually seen wearing a white lab coat, but changed into more casual clothes when he went to Las Vegas to ambush Alice.
- Isaacs is named after actor Jason Isaacs who portrayed an unnamed doctor from the first film and was created to fulfill Birkin's role in the sequel.
- This clone of Alexander Isaacs indeed bears similarities to William Birkin, whether intentionally or not. Both are blonde Umbrella scientists affiliated to an extent with Albert Wesker (especially concerning the death of James Marcus), both are attempting to reach a type of godhood (the G-virus for Birkin, the secret of Alice's T-virus immunity for Isaacs), and both transform themselves into tentacled, clawed monsters in a state of desperation (the "G" creature for Birkin after being mortally wounded, and a Tyrant variant for the Isaacs clone after being bitten by an infected).
- This clone appeared to be similar in nature to Alice, "Bad Rain" and the clones of Carlos Olivera and James Shade in that they were clones of real people, but lacked this knowledge. Instead, they acted as Umbrella employees in various functions. This is indicated by the fact that unlike the other Isaacs clone encountered by Alice, this one was clearly subservient to Albert Wesker and the other Umbrella higher-ups instead of being in charge himself or at least believing himself to be. The Umbrella Committee also possessed the power to order his death which they were unlikely to have the ability to do if he were aware of his true identity and was thus in charge.
- Due to the death of this clone, the real Alexander Isaacs was believed to be dead for years by both Alice and Claire Redfield until Alice met the second Isaacs clone.
- It is unclear how Claire came to know of his death as she departed in Extinction before Alice faced off with him and Alice never mentioned it to her afterwards. However, in The Final Chapter, Claire was aware of Alice killing this clone and asked about it after learning of the approach of what was believed to be the real Isaacs.