- Red Lynx / Lana Durand Rose (first appearance) (flashback and main story; origins revealed)
- Horizon Labs
- Max Modell
- Count Dracula (first appearance)
- Vampire Spawns
- Michael Morbius the Living Vampire (first appearance)
- Hobgoblin / Harry Osborn
- Norman Osborn
- The Goblin (illusion only)
- Emily Rose (flashback and illusion only)
- Jedediah Durand (single appearance; flashback only; deceased)
- Cristina Rose (single appearance; flashback only; deceased)
- Russell Durand (first appearance; cameo)
- Aunt Martha (first appearance)
- Katrina Romanoff
- Maxine Joan (cameo)
Lana Durand Rose, a young orphan operating as the Red Lynx, is standing before the grave of her maternal aunt Emily Rose Osborn, voicing her grievances over their past; Emily blamed the death of her sister on Lana (since Lana's mother died after childbirth) so hardly, that Emily even hired an unknown mercenary to kill Lana and her father Jedediah. Though Jedediah died trying to protect his daughter, Lana was saved by Natasha Romanoff / Black Widow, and taken to be raised by a family of Wakandans to be presumed dead for Emily. In Present Day, Lana is disappointed that despite what her aunt committed, Emily is still remembered by Norman Osborn as a "perfect wife", and destroys Emily's gravestone, declaring that she will never be a part of the Osborn name. Later on, she overhears of an riot taking place in an Oscorp facility and, donning her Vibranium-powered nanosuit, sets out for action.
In the facility, scientists are being attacked by Dr. Michael Morbius, a scientist suffering from a rare blood disease who attempted to cure himself with DNA from vampire bats, but instead became afflicted with a new form of vampirism, giving him metahuman abilities, including the need to absorb other humans' life force to remain alive. The Avengers (Black Widow, Tony Stark / Iron Man, Steve Rogers / Captain America, Carol Danvers / Captain Marvel, Aamir the Phantom Tiger, Kate Bishop / Redhawk, Maverick, Scott Lang / Ant-Man, Crystal, Lockjaw, T'Challa / Black Panther, Thor, and Bruce Banner / Hulk) and Red Lynx make it there and defeat Morbius, and take him to Horizon Labs to be analysed by Max Modell. After Banner and Lang detect Darkforce particles in Morbius' nervous system, Aamir enters the Astral Plane to find out where the Darkforce is coming from, envisioning vampires on Transylvania in the progress. Rogers soon deduces it is the work of the vampire king Count Dracula, who rules the dark underground of Transylvania long before World War II, and T'Challa assumes it has to do with a old Vibranium war staff which is hidden somewhere in Transylvania decades ago. Morbius soon recovers and (using one of the Space Stone prototypes) teleports to Transylvania, where he seeks a safe place to hide, but not before Lana implants a tracker on Morbius' neck so the Avengers will know where to find him. Meanwhile, Osborn overhears the Avengers' conversation with Modell through one of his drones until the Goblin takes control of his mind and body, for which he orders Harry to don the Hobgoblin suit and find the war-staff (which contains a crystal shard with the energies of the Reality Infinity Stone) in Transylvania. As Harry does so, Norman regains control and attempts to stop him, but fails and ends up fighting the Goblin's essence to no avail. Through one of Oscorp's drones, Lana learns of what Osborn has sent Harry for, becoming aware of his plan.
The Avengers and Red Lynx arrive in Transylvania, where they battle every vaampire in their way. Red Lynx proves to be the most effective fighter, who defeats many of the vampires more effortlessly. Black Widow explains that one year ago, Lana had found and explored a hidden lab beneath a neighbor's farm and, after accidentally breaking one of the chemical capsules, exposed herself to a serum containing feline DNA and Vibranium-powered particles which gave her her powers. After spending one week living in the jungle, Lana donned her Vibranium suit, which was provided for her by the Dora Milaje, and spend her lifetime exploring the world to destroy everything the Osborn family is creating or searching for. Back in the Present, the Avengers encounter Dracula, who reveals his plan to use the Vibranium war staff to unleash his Darkforce to half of the planet, and turn his inhabitants into vampires like Morbius. Dracula also reveals his intentions of converting Morbius to his will due to his strong potential as a vampire. As the heroes battle Dracula and his spawns, Hobgoblin arrives in Transylvania and, taking advantage of how occupied the heroes are, searches for the war staff. Red Lynx, however, notices Hobgoblin in the area and stops him, proceeding to beat him under submission while reprimanding him for having never stepped out of his father's shadow. Seeking to avoid becoming Dracula's puppet, Morbius searches for and finds the war staff, but is unable to control its power, causing him to create virtual reality illusions based on dead evil souls. Those include, to Harry's shock, his mother Emily.
Harry unmasks himself to be sure his mother will recognize him, but unfortunately, she begins attacking him, taunting that she never really loved Norman, and was interested in nothing more than his massive amounts of fortune. Just then, Red Lynx (right after hearing how Emily was "even happy that her sister was gone") eventually attacks and destroys the illusion (as Emily is shown getting dragged into the underworld by some of Dracula's spawns) and leaves Harry to sob alone. Morbius continues trying to control the war staff until Black Widow and Black Panther knock him out and disarm him. Dracula attempts to seize the staff, but only until Red Lynx obtains it first and teleports herself and Dracula into New York. Dracula attempts to drain Lana off her lifeforce with a bite in her neck, but the Vibranium particles powering her blood effectively overwhelm Dracula like the effects of sunlight, and allowing Lana to control his vampire army. Determined to end Dracula's reign, Lana manages to destroy the war staff, disintegrating the vampires and causing the dark souls to seal Dracula away into the underworld for all eternity. As a traumatized Harry is retrieved from Transylvania by Oscorp's security guards, Morbius is taken to the Vault, where he is expected to be cured of his vampiric condition. Meanwhile, Romanoff is in her home with her daughter Katrina while Lana (now living with her paternal uncle Russell and more loving aunt Martha) moves to a new home near the Romanoffs' residence.
- Laura Bailey as Black Widow / Natasha Romanoff
- Kate Higgins as Red Lynx / Lana Rose
- Mick Wingert as Iron Man / Tony Stark
- Roger Craig Smith as Captain America / Steve Rogers
- Jennifer Hale as Captain Marvel / Carol Danvers
- Travis Willingham as Thor
- James C. Mathis III as Black Panther / T'Challa
- George Newbern as Hulk / Bruce Banner
- Eric Bauza as Aamir the Phantom Tiger
- Ali Hillis as Redhawk / Kate Bishop
- Josh Keaton as Ant-Man / Scott Lang
- Kari Wahlgren as Crystal, Aunt Martha
- Tara Strong as Katrina Romanoff
- Matthew Mercer as Michael Morbius, Jedediah Durand
- Fred Tatasciore as Max Modell
- Corey Burton as Dracula
- Sam Riegel as Hobgoblin / Harry Osborn
- Jeffrey Combs as Norman Osborn, the Goblin
- April Stewart as Emily Rose Osborn
- The moment when Lana destroys her aunt's gravestone is similar to the moment Carol Danvers / Captain Marvel confronts her father Joseph Danvers in his grave and destroys his gravestone in The Life of Captain Marvel Issue #1.
- Emily revealing that she was interested in her husband's money is a reference to the 2002 Spider-Man film, on which it was hinted that Harry's mother had left Norman and taken some of his money with her.