- "Dr. Foster did his best to keep me safe, but others at S.H.I.E.L.D. saw an opportunity in my affliction. They built me a containment suit so I could control my phasing, and trained me to be a stealth operative. They weaponised me. I stole for them, spied for them. I killed for them. And in exchange for my soul, they were going to cure me. They lied."
- ―Ghost to Ant-Man
Ava Starr is the daughter of Elihas and Catherine Starr, who gained the ability to render herself intangible and generate extreme amounts of power following a quantum accident, which killed her parents. At a young age, S.H.I.E.L.D. began taking advantage of her powers, enlisting her as a stealth operative under the moniker of Ghost prior to the HYDRA Uprising. Under Bill Foster's care, Ava realizes that she is slowly dying due to a lack of quantum energy, which she involuntarily harnesses.
Within weeks of succumbing to her disease without a cure, Ava learns that an updated version of the Quantum Tunnel, a gateway to the Quantum Realm engineered by Hank Pym has been completed, and embedded into a portable lab. Her plans to harness quantum energy from the Quantum Realm conflict with Pym's plans to rescue Janet van Dyne, whose survival in the Quantum Realm relies directly with the quantum energy Ava is seeking to extract. Ava begins making attempts to steal the lab by force, putting her in conflict again, this time with Ant-Man and the Wasp. At the verge of dying, Janet transfers some of her energy to Ava, temporarily stabilizing her abilities. With this, she slowly makes a recovery, and goes into hiding with Foster.
- "I doubt Hank ever mentioned my father. Why would he? Elihas Starr. They were colleagues at S.H.I.E.L.D.. Quantum research. Until my father dared disagree with the great Hank Pym. You had him fired. Oh, and discredited for good measure. My father tried to continue his research on his own, desperate to restore his name. So, he took risks. Too many, until something went wrong. He told us to run. I could tell he was scared. I didn't want him to be alone. When I woke up, my parents were dead. I wasn't so lucky."
- ―Ava Starr
When rescue crews arrived, they were unable to touch her as she had become intangible from the accident. She was placed in a shelter and first encountered Bill Foster there, who gave her a toy. Although she was upset that she was unable to hold it, Bill encouraged her to focus her powers, and she was eventually able to solidify and pick it up. Bill promised to find a way to cure her condition and began to act as a surrogate father, developing the quantum chamber to allow her to briefly stabilize and ease her pain.
Observing the potential asset her powers could become, S.H.I.E.L.D. took Ava and began to train her in espionage so that she could go on missions to take down threats that proved too difficult for conventional operatives. They developed the Ghost Suit for her to harness her abilities, granting her the option to slip between intangible and solid states, and promised to help find a way to cure her. Over the course of her time in the field as well as the prolonged suffering caused by her quantum displacement, Ava became hardened and extremely vicious, eventually realizing that S.H.I.E.L.D. had no intention of finding a cure.
When S.H.I.E.L.D. collapsed, Ava was taken in by Bill, who began to assist her in researching a cure as her condition started to deteriorate. 
Finding a Cure
Clashing with the Pyms
After Hank shrunk the lab and left with Hope and Scott, Ghost suddenly materialized a short distance away, tracking their van to Sonny Burch's restaurant. After Burch attempted to double-cross Hope, Ghost waited until Wasp had defeated Burch's mercenaries and taken the final component before appearing and engaging Wasp in a duel for its ownership. Despite gaining an upper hand on Wasp, Ghost's plans were thwarted when Ant-Man arrived. The two managed to defeat her, but Ghost managed to coerce Hank to give her the lab and fled before Scott or Hope could intervene.
Arriving at her hideout, Ghost placed herself into the quantum chamber to temporarily stabilize herself. While she was recovering, Hank had successfully tracked down the lab using re-engineered tech from an earlier Ant-Man suit and sent Hope and Scott there to retrieve the lab. Although Ant-Man and the Wasp were able to enter the building and locate the lab, they were knocked unconscious and restrained along with Hank.
When Scott awoke, Ghost explained that she needed the psionic link he shared with Janet van Dyne in order to track her down in the quantum realm and extract her quantum energy to permanently fix her displacement. She revealed that she had been working with Bill Foster to find a cure, and when Hank and Hope refused to cooperate because of the potential that Janet would die during the extraction, Ghost bitterly retorted by reminding Hank of his role in her father's expulsion and her current state.
Hank feigned a heart attack to trick Bill into opening the Altoids tin, releasing a group of enlarged ants and allowing the Pyms and Scott to escape with the lab. Furious, Ghost planned to kidnap Cassie Lang as a ransom for the lab, but Bill told her he would not continue to help her find a cure if she did this. Still set on getting the lab, Ghost left to track down the Pyms again.
Ghost spied on Burch's interrogation of Luis and learned that the lab was currently at a forest. She then damaged Burch's car to slow him down and headed for the lab.
Later, after Hank and Hope were arrested, Ghost killed Stoltz and managed to take the lab herself and set it up to prepare her energy extraction from Janet Van Dyne. However, she was then confronted by Ant-Man, having previously freed the two Pyms from custody. They and their ant buddies were able to sabotage the extraction and allow Hank to enter the Quantum Realm so he could reunite with Janet, with the ants themselves forcing Bill out of the building before it shrank back to luggage-size. A three-sided car chase then took place between the Pyms, Sonny, and Ghost herself in San Francisco.
During the car chase, Ghost had managed to get the Pyms' lab from the others shortly before losing it again in her struggle to extract energy from the Quantum Realm. Eventually, after Giant-Man took the lab from Sonny and struggled to breathe, he dropped the lab only for Ghost to retrieve it and grow it to normal size with the remote that she stole from Luis.
As Hank was preparing to return to the real world with Janet, Ghost began her process of extracting energy to repair her body, ignoring Bill Foster's warnings about doing so and his promises that Janet would be able to help her. She was then stopped by Scott Lang and Hope Van Dyne after the latter recovered Ant-Man from San Francisco Bay, and kept at bay until Hank and Janet were able to successfully return from the Quantum Realm. By then, her body was beginning to fall apart completely; however, she was saved by Janet, who transferred a portion of quantum energy into her.
Afterward, Ghost proceeded to escape the scene with Scott Lang, Bill Foster, and the Pyms, with Janet promising to fulfill the repair of Ghost's body.
Ghost has been trained by S.H.I.E.L.D. to become an elite and ruthless stealth operative tasked with infiltrating and eliminating criminal organizations, terrorist cells, and other threats. She holds a grudge against Hank Pym for expelling and discrediting her father, inadvertently leading to the accident that killed him and his wife as well as afflicting her with molecular disequlibrium.
Due to the years of chronic pain Ghost experienced as a result of this, she was desperate enough to do anything to permanently fix her condition, especially when she learned that she had only a few weeks to live. Ghost’s limited time to live, chronic pain, and desperate need to survive pushed her to act with extreme aggression and impatience. She was planning to extract Janet van Dyne's quantum energy despite the fact the process could potentially kill Janet and even considered kidnapping Cassie Lang as leverage to force Scott to give her the Pym laboratory. Ghost was unwilling to hear pleas of more peaceful yet uncertain means of curing her condition, as she was acutely aware of her limited lifespan. Having been promised a cure by S.H.I.E.L.D. that was not delivered made Ghost distrustful of anyone who urged patience and vague plans for a cure to her condition. Although she shares a somewhat familial bond with Bill Foster, who assisted her in attempting to find a cure, she violently threw him aside when he tried to stop the quantum energy extraction.
Despite Ghost’s brutal exterior, she's not a heartless person by nature. While Ghost's condition and imminent death caused her to act ruthlessly to survive, she still has a sense of morality, feeling shame for her actions as an assassin of S.H.I.E.L.D due to the fact that the organization never had any intention of finding a cure and all she did for them did nothing to help her, showing she is able to feel remorse for committing actions that were not beneficial in her attempt to cure her condition. Ghost has also proven to be capable of showing compassion and regard for others' well-being, particularly to those close to her. This is best exemplified when she urges Bill to abandon her, warning him that he will also be pursued by the authorities if he continues to act as her caretaker. Also, despite what the Pym family's actions caused her, Ava was willing to accept help from them and seems to be on much better terms with them after Janet returns and they begin extracting quantum energy to gradually cure her quantum illness.
Powers and Abilities
- "They call it "molecular disequilibrium". A rather dull name, I think. Doesn't quite do justice to what it means. Every cell in my body is torn apart and stitched back together, over and over every day."
- ―Ava Starr
- Intangibility: Ghost can phase through solid objects and living beings at will. The use of her powers is accompanied by flickering, prismatic afterimages of her body as she quantum shifts through space. With the aid of her suit, she can choose whether to become solid or intangible, which allows her to quickly evade attacks and counterattack in tandem; for example, she became intangible to drop through a table while smashing Wasp into it, vaulted through a truck and used the momentum to knock one of Burch's henchmen off his motorcycle, and phased through Hank's van before solidifying to kick Wasp onto the street during a chase. Solidifying herself while phased through solid matter has destructive effects on the original object, as she forced Hank Pym to give her the lab by threatening to solidify her phased hand inside his neck. She was also able to phase her hand into Stoltz's chest and crush his heart.
- Invisibility: Ghost is able to pass in and out of the visible spectrum. She first used this power to spy on Hank, Scott, and Hope after they shrunk the lab and fled. In fights, she was shown vanishing then re-appearing to launch a surprise attack against Wasp during the restaurant lobby skirmish, and also appeared in the midst of Burch's interrogation to find out where the lab was from Luis.
- Self-Augmentation: Ghost is able to amplify the amount of force behind her attacks while phasing, as a single kick was able to launch Ant-Man through several walls.
- Acrobat: Ghost is skilled with acrobats, which allowed her to vault over a car with ease. She also incorporates gymnastics and acrobatics into her fighting style as she battles opponents.
- Combatant: Ghost, having received extensive training from her time as an assassin for S.H.I.E.L.D, is an excellent fighter. She was able to fight evenly with both Ant-Man and Wasp with the use of her powers.
- Ghost Suit: A full-body suit that was designed by S.H.I.E.L.D. to help her better control her powers. The suit allows Ghost to selectively phase through matter at will, allowing her to rapidly switch between intangibility and tangibility for both stealth and offensive purposes.
- Quantum Energy Chamber: Created by Bill Foster, the chamber releases waves of quantum energy which temporarily stabilize Ghost's disequilibrium.
- Elihas Starr † - Father
- Catherine Starr † - Mother
- Bill Foster - Adoptive Father and Former Situational Enemy
- Scott Lang/Ant-Man - Enemy turned Ally
- Hope van Dyne/Wasp † - Enemy turned Ally
- X-Con Security Consultants - Enemies turned Allies
- Hank Pym † - Enemy turned Ally
- Janet van Dyne † - Attempted Victim turned Healer
- Cassie Lang
- S.H.I.E.L.D. (First Incarnation) - Former Employers
- Sonny Burch
- In the comics, the Ghost was a male anticapitalist saboteur who went unnamed. A brilliant inventor, he created a battle suit with his personally designed GhostTech that allowed himself or any object he touched to become invisible or intangible.
- The Ghost is the third character in the Marvel Cinematic Universe to be depicted as a different gender from their counterpart in the comics, following Jeryn Hogarth and the Ancient One.
- Ghost is the second female main antagonist in a Marvel Cinematic Universe film, the first being Hela.
- Ghost is also the second main villain in a Marvel Cinematic Universe film who became good, the first being Loki.
Behind the Scenes
- Ghost's first name was originally listed as Dawn.
- Tamiko Brownlee was a stunt double for Hannah John-Kamen in the role of Ghost.
- Eli Logue was a stand-in for Hannah John-Kamen in the role of Ghost.
- Stephen Broussard states that Ghost is: "a villain that doesn’t want to take over the world, or get rich or do anything that has these world stakes. It’s literally about survival that makes her a villain, and the complication is that she needs what our heroes need. So suddenly you have heroes and villains after the same thing for very grounded, relatable and emotional reasons.”