Further notes

As the final boss of Leon and Helena's story, Derek C. Simmons is a massively powerful and persistent opponent. Over the course of the battle, he will adopt many different forms, which also have their own variations along the way due to his C-Virus infection.


The "Centaur", so named in the original Japanese script for the Derek's 1st Transformation file, is a quadrupedal canine-like creature. Although Simmons is fast and powerful in this state, he reverts to human form after suffering enough damage, providing an opening for Leon to give him a beatdown. After his first defeat, Simmons then mutates into a stronger version of the "Centaur", which is more true to its namesake by converting the head into a bony structure vaguely resembling a human torso. In this state, Derek can transform his spine into a spear and fire shards of his bones as projectiles. This version of the "Centaur" exposes his deformed human face, which serves as a weakpoint. Dealing enough damage to his human face will speed up the fight.

The "Centaur" mutation is the first form of Simmons that Leon and Helena battle after cornering him on the train. Halfway through the fight, he transforms into the second version of the mutation, which he uses for the rest of the battle.

Simmons mutates into both versions of the "Centaur" when pursuing Leon, Helena and Ada Wong outside the Quad Tower. His second mutation gains a new attack where he uses the spear appendage to stab the player and drag them towards him, where he strikes them with a barrage of small tentacles.


As the C-Virus continues to develop within Simmons, he mutates into a gigantic creature resembling a theropod dinosaur. Lacking the unique abilities of the "Centaur" mutations, this form relies solely on brute strength to attack the players, attempting to crush them underfoot or even devour them. The main weakpoint for this form is the large eyeball located in the theropod's mouth - the exposed sections of flesh on its back are also vulnerable, but the players will have to destroy the protective scales over them first. Simmons can attack the helicopter Ada pilots by throwing projectiles with his mouth or leaping an impressive distance into the air to try and tackle her with his body. He also occasionally roars to disorient the player characters, dealing minor damage should they happen to be close to him.

Simmons adopts this form when Ada, Leon and Helena encounter him outside the Quad Tower lobby. As with his previous mutations, heavy damage causes him to revert to human form and leaves him vulnerable to hand-to-hand combat. At a certain point in the battle, a BSAA soldier will arrive in a buggy armed with machine guns which can be used to damage Simmons as he chases the buggy around the courtyard. However, he quickly destroys the vehicle and kills the driver, forcing Leon and Helena to continue the battle on foot. Another gun truck is present near the lower-left side of the entrance, but Simmons will destroy it if he charges into it.

To speed up the battle, Leon and Helena can lure Simmons towards the large tanker in the battle area. If he charges into it, the fuel inside will leak out, which can be shot to set him on fire. In addition, shooting one of the red barrels scattered around the arena when Simmons is nearby will cause significant damage to him.

Recovery form

After suffering severe injuries at the hands of Leon, Helena, and Ada, Simmons shifts to a more humanoid form as he tries to heal his wounds. This mutation is notably less drastic than the prior transformations - his entire human body is visible and vulnerable to damage. A mass of bone and muscle emerging from his back appears to weigh him down to the point of immobility. Although this form is the weakest of his mutations, Simmons is not defenseless - he attacks the players with a large, scorpion-like tail, which he also uses to snare C-Virus Zombies and break them down into matter that he absorbs to heal himself.

Leon and Helena encounter this form of Simmons on the roof of the Quad Tower, impaling several zombies to regenerate himself. His wounds are not completely healed, however, leaving him vulnerable to his foes' attacks. After suffering further damage, Simmons collapses as a horde of zombies start to devour his body. Leon and Helena take advantage of the moment to escape the area, and thus miss Simmons beginning to consume the zombies to fuel his continuing mutations.

Mega Fly

After consuming the zombies that attempted to feast on him, Simmons mutates into a giant monstrosity resembling a housefly. This form is significantly larger than the prior mutations, with the ability to spit toxic globs at Leon and Helena. Although Simmons can use his new wings to fly, his huge size limits the advantages of his new maneuverability. Most of his body is protected by a strong exoskeleton, but his eyes are vulnerable to damage, and being shot there also interrupts his attacks.

This mutation of Simmons attacks Leon and Helena as they try to reach the helipad, successfully knocking Leon off the platform. While Helena operates a crane to help Leon reach the other side of the platform, Simmons continuously assaults him with glob attacks and eventually tries to strike him at close range. Leon manages to stall Simmons long enough to reach the helipad, where the villain undergoes one final mutation.

Simmons' final form enlarges his mandibles into large pincers, and his limbs have become many times larger and stronger than before. He will use his new limbs to smash the helipad, attempting to crush the player. His pincers will cover his head whenever the players fire at his eyes, protecting his old weakspots - however, the exposed joints of his limbs are still vulnerable to damage, and the limbs can be severed with sufficient punishment. Additionally, some of Simmons' claw swipes will prompt a Quick-Time Event if the player is nearby - success in the event will trigger a short cutscene where Leon or Helena climbs the limb and plants a grenade in its joint, instantly severing it.

When one of Simmons' limbs is severed, he will try to regenerate by consuming the zombies that appear on the helipad. This can be prevented by killing the zombies before Simmons can ensnare them with his tentacles, but Simmons will simply try again after a short period of time. In order to make any progress, Leon and Helena must pick up the broken lightning rod lying on the roof and impale a zombie with it. The next time Simmons tries to regenerate, he will accidentally absorb the lightning rod along with the zombie, which causes him to suffer a massive electric shock. As he recovers from the damage, the lightning rod will fall to the roof; one player should retrieve it and impale another zombie, while the other player targets Simmons' remaining limbs and keeps the other zombies off of their partner's back.

After losing enough of his limbs or taking enough lightning bolts, Simmons collapses onto the platform. Leon and Helena must impale another zombie with the lightning rod before shooting Simmons' eyes - alternately, they can bring the lightning rod directly to him and stab him in the eye with it. Either way, Simmons will be left vulnerable to a final lightning strike that knocks him off the roof.

Leon and Helena subsequently manage to reach the helicopter, only for the battered Simmons to climb up to the helipad in a final desperate attempt to kill them. However, this would be Simmons' final mistake - using a rocket launcher in the helicopter, Leon and Helena blast the villain in the head, causing him to lose his grip and plummet back down the tower shaft to his ultimate demise.