With six installments, the Resident Evil franchise is arguably the most successful adaptation of a video game property. Few would accuse them of being high art, but even fewer would accuse them of lacking some seriously creepy beasts.
Each installment of the franchise managed to toss a new horrific monster at Alice and whoever else had managed to survive up until that point. More impressive yet is how the series managed the task of consistently outdoing itself. On top of the types of zombies seen in other horror movies, Resident Evil has gifted the horror genre with some very memorable monstrosities.
Zombies
It says a lot about the Resident Evil franchise that zombies are its least intimidating monsters. While they are scarier than a Romero zombie (these can run), they're nothing compared to the Umbrella Corporation's other heinous creations.
Standard undead play a part in every RE movie, but they're never a huge focus in comparison to the film's main baddie(s). Compared to what Alice, Jill, and Claire face in some of the sequels, zombies are a mild inconvenience.
Cerberus
It may not be one of Milla Jovovich's best movies, but the original RE has made her an action-horror icon for a reason. Her fight with the Cerberus is visceral, and arguably one of the first movie's best scenes.
The scariest appearance is in the original, if only because of how they're presented: snarling and shrouded in darkness. In Resident Evil: Afterlife, their entire bodies can split in two - with waggling tendrils and random teeth à la The Thing - but there's a little too much CGI for them to be truly scary anymore.
Tyrant
Game of Thrones' Iain Glen was turned into quite the creature in Resident Evil: Extinction. But his character, Dr. Alexander Isaacs, was a monster long before the zombie bite.
After Isaacs injects himself with the anti-virus, one of his supposed cohorts shoots him in the chest. It triggers an internal reaction, giving the doctor a transformed, rotted appearance. He can shoot deathly tendrils across the room, and even gave Alice a run for her money. Regardless, he couldn't avoid a laser field (even if it was revealed to be merely an Isaacs clone).
Kipepio
Resident Evil: The Final Chapter delivered two new interesting monsters to the fold. The first one seen is Kipepio, with it chasing Alice through an apocalyptic wasteland in the film's opening scene.
Kipepio is not far off from being a zombified dragon. Instead of breathing fire, though, it has a massive tail that can split into several sharp, flying tendrils. More deadly yet is the hooked part of its tail, which can easily rip the top off of a car. It does, however, have a weakness to claymores.
Majini Zombies
The first time the dead-eyed Majini zombies are seen in Resident Evil: Afterlife, they yank one of the film's more contemptible characters down a well.
The first appearance is shocking, especially considering it's a jumpscare in a series filled front to back with them. The Predator-like mandibles on its mouth make it a suitably more terrifying rendition of the films' regular zombies. Once those four sections of jaw wrap around the victim's head, they're helpless.
Licker
The Licker may be one thing about Resident Evil that makes no sense, but it's a terrifying monster. With a tongue that droops to the floor, it has an appearance not unlike those created by H.R. Giger.
Like most of the other Resident Evil creatures, the Licker is really just a mutated variation of a human being: the human being mutates into a zombie, then the zombie mutates into the Licker. The movies incorporate the design from the video games, giving this monster a horrifying exposed brain.
Nemesis
A mutated version of one of the original film's protagonists, Nemesis is the highlight of the otherwise dour and boring Resident Evil: Apocalypse.
A hulking humanoid with a mouth like Hellraiser's chattering Cenobite, the Nemesis also comes adorned with a ridiculously effective chain gun. Dr. Isaac's Tyrant is technically the next step in Nemesis' evolution, but Nemesis possesses the overall more terrifying appearance. It may be slower, but it's one of the more deadly creations in Resident Evil.
Axeman
Not only does the Axeman possess one of the best weapons in Resident Evil, but it also possesses one of the most intimidating appearances.
In the case of Axemen, appearances are not deceiving. First introduced in Resident Evil: Afterlife, the best appearance of Axemen comes in the follow-up, Resident Evil: Retribution. Namely, the scene where Alice and Ada Wong have to fight off two of them back to back. The sheer size and brutality of Axemen make them a force to reckon with.
Bloodshot
It may not have actually been the Resident Evil franchise's "final chapter," but the sixth Resident Evil film does have the most ferocious monster in the series' history.
Bloodshot (who isn't named in the film) has been stuck in The Hive for its entire lifespan. That makes it even more dangerous when it's finally released. It may have photosensitivity, but Bloodshot still seems a cut above any other T-Virus mutation. It's perceptive and cunning whereas the remainder basically just attack if they see the target.