Robert Callaghan, also known by his alias as Yokai, is a university professor turned supervillain and the main antagonist of the 2014 Disney animated film Big Hero 6, the first Disney animated film based on a Marvel Comic.

He was voiced by James Cromwell.

Appearance and Personality[]

Callghan is a tall, middle-aged man that has grey hair and a tuxedo. As Yokai he wears a pitch black jacket, dark shirt, dark jeans and shoes, and wears a red and white Kabuki mask over his face.

Robert Callaghan/Yokai is very ruthless, vengeful and relentless as he is shown to have very little remorse for the lengthy list of crimes he committed during his mission to kill head executive Allistair Krei in order to avenge his daughter. He can telepathically lead a swarm of his microbots to his advantage with a headband.


Professor Callaghan was an aspiring man; a world-renowned scientist, praised for his innovations on the foundations of robotics, as well as the creation of Callaghan's Laws of Robotics. With such recognition and knowledge, Callaghan put himself to good use by teaching as the head professor at the San Fransokyo Institution of Technology, where he mentored such prodigies as the brilliant Tadashi Hamada, who admired him greatly. Notably, though he was passionate about science and robotics, Callaghan's true love lay within his daughter, Abigail, who was once a test pilot for Krei Tech Industries: the world's leading technology industry, owned and operated by San Fransokyo's own Alistair Krei. One of Krei's latest ambitions, at the time, was the desire to revolutionize transportation through the use of portals—a project dubbed "Silent Sparrow". Unfortunately, during the experimental test run, a malfunction occurred in the system, and Abigail was lost in the portal, eventually presumed to be deceased. The tragedy left Callaghan with a hardened heart, and since, he swore revenge on Krei, eventually descending into villainous madness as time would pass and his lust for vengeance strengthened. This would ultimately lead to the abandonment of Callaghan's former identity, and the birth of Yokai.

Role in the film[]

Callaghan is first introduced at the San Fransokyo Institute Technology, where he is introduced to Tadashi's younger brother, Hiro Hamada, a young genius. Tadashi reveals Callaghan is the renowned creator of the very technology Hiro uses for bot-fighting purposes, and the cunning professor subtly reprimands the boy's actions, cleverly convincing him to join the school alongside his brother, to use his brains for greater purposes. In order to gain acceptance, Hiro builds, what he calls, the Microbots, a robotic army of miniature bots capable of becoming anything the mind can conceive, through the use of a telepathic transmitter. Hiro takes his newfound invention to the school's annual student showcase, where several up and coming geniuses showcase their unique inventions in an attempt to receive acceptance into the university.

Hiro's Microbots immediately impress Callaghan, though they also catch the attention of Alistair Krei. Krei immediately expresses interest in purchasing Hiro's inventions, but because of their past history with one another, Callaghan intervenes, warning Hiro to steer clear of the tech-guru, as (according to Callaghan) he only uses the foundation of science for his own selfish gain. After some consideration, Hiro takes Callaghan's advice, and refuses to sell his creation. And with that, Callaghan grants Hiro acceptance into the school.


Yokai confronts Hiro and Baymax at the warehouse.

However, after Hiro's departure, Callaghan steals the Microbots for his own nefarious purposes in seeking revenge on Krei, and to cover his tracks, the professor sparks a huge and deadly fire, setting the showcase hall ablaze. As panicked attendants barely escape the disaster with their lives, Tadashi gets word that Callaghan is still within the building, and rushes inside to rescue him, losing his life in the process once the building violently explodes, and leaving Callaghan to be presumed dead. Unbeknownst to anyone, however, Callaghan used the Microbots to save himself, and proceeded with his plot to get revenge on Alistair, under the guise of a mysterious and elusive masked figure known as Yokai. Yokai sets up a base of operation within an abandoned warehouse near the city's harbor, where the Microbots are massed produced to create an overwhelming army. One day, Hiro and Tadashi's healthcare robot, Baymax, stumble upon the warehouse and discover the vast army of Microbots. Yokai notices their presence, and immediately uses the bots to attack, though the duo barely manage to escape.

Yokai BigHero6 Trailer

Yokai during the chase throughout San Fransokyo.

Realizing the fire that killed Tadashi was no accident, and was merely used as a means to cover the tracks of the Microbot theft, Hiro transforms Baymax into a crime-fighting robot and heads out to the warehouse in the middle of the night in hopes of capturing Yokai and bringing him to justice. They use the only Microbot left in their possessions to track down the masked villain, leading them to the trading post. There, Yokai emerges from the foggy bay, with a piece of a dismantled machine, prompting Hiro and Baymax to take cover in silence. They remain hidden until Hiro's friends, and Yokai's former students (Fred, Wasabi, Honey Lemon, and Go Go Tomago) arrive, causing enough noise to catch Yokai's attention. Once spotted, the masked villain attacks the group, and makes an attempt to kill them, believing they've seen too much (according to Fred). Using the Microbots, Yokai rampages through the city, after the team's vehicle, making several attempts to destroy them before they can escape. Though Yokai's attempts nearly succeeds, the team eventually manages to evade him by accidentally driving their car into the sea and apparently drowning. Yokai looks upon the damage, and believes them to be dead, thus prompting him to depart.

Yokai on Akuma Island

Yokai battles the team on Akuma Island.

However, the team survives and manages to return to dry land and safety. Afterwards, under the guidance of Hiro, they use their technological advances to become a superhero team known as Big Hero 6, with hopes of stopping Yokai's plot and saving the city. Meanwhile, Yokai continues onward with his revenge scheme of recollecting the missing pieces to the Silent Sparrow portal, and does so by infiltrating an abandoned facility on Akuma Island. Notably, the facility once belonged to Krei, and was the area in which both Silent Sparrow and Abigail's supposed death took place. Baymax is able to track the villain's whereabouts and the team heads over to the island for another battle. They find a recording that reveals the facility once belonged to Krei, and the latter ambitions, at the time, was the desire to revolutionize transportation through the use of portals—a project dubbed "Silent Sparrow". Before Yokai arrives, they find a recording that reveals what happened to Abigail. They also learn the incident resulted in the closure of Krei's facility. This leads the group to believe Krei is the man behind the mask, wanting to rebuild his portal. Just then, Yokai finds the team and attacks. A battle ensues, and each member tries to remove the mask, knowing the mask is the true source of Yokai's power.

Yokai's Reveal

Yokai's identity is revealed to be Callaghan.

After many failed attempts, Hiro manages to accidentally knock off the villain's mask, and Yokai's true identity is revealed to be Callaghan. A confused Hiro asks the circumstances of Callaghan's survival, and the latter reveals his use of the Microbots to shield himself from the flames and escape his own death. Saddened by the fact that Tadashi died for nothing, Hiro explains how the former died trying to save the professor, only for Callaghan to coldly claim Tadashi running into the burning building was his own mistake. Angered by these words, Hiro orders Baymax to kill Callaghan, much to the latter's horror. Though the robot denies at first, being a healthcare robot unable to perform violent acts on human beings, Hiro removes the bot's healthcare chip, leaving only his battle-centric programming within his system and turning him into a mindless killing machine. The now vicious robot then proceeds to attack a powerless and fearful Callaghan, but fortunately for him, the other team members intervene, knowing murder would be the wrong choice, as revenge is a hollow victory. Nevertheless, Baymax continues to attack, and in the midst of the chaos, Callaghan manages to retrieve his mask and flees the scene, along with the remaining piece of the portal.


Callaghan battling Hiro and the team as his portal causes mass destruction.

The following day, Yokai intercepts Krei's latest ceremony, immediately capturing the tech-geru before revealing his true identity. Krei is briefly taken aback by Callaghan's appearance, having believed him to be dead, but his confusion is quickly replaced by pure fear as Callaghan confronts his nemesis on his daughter's demise, blaming Krei for the preventable tragedy, and announcing his plot to use the newly rebuilt Silent Sparrow portal to destroy all Krei has ever built, before killing Krei, himself—a plot that would ultimately lead to the downfall of San Fransokyo. Krei pleads for mercy, but with Callaghan's mind set, the portal is activated, being held high above Krei's building by the Microbots, thus beginning the destruction. Just then, Hiro arrives alongside his teammates and confronts the former professor, demanding he call of his plot as Abigail wouldn't approve. When Callaghan argues against such claims, Hiro continues, explaining that revenge is a hollow victory, specifically with loss, having learned such a lesson through personal experience. Realizing what Hiro says may be true, Callaghan falls into a state of moral thought, only to be drawn back into a murderous rage once Krei makes a sleazy attempt to escape the situation, igniting a deadly battle against Yokai and the Big Hero 6 team.

Hiro Baymax Yokai Final Battle

Hiro and Baymax decide to spare Callaghan's life.

Hiro orders his teammates to aim for the villain's mask, but Callaghan proves to be a nearly unstoppable force, and quickly imprisons each member of the team in a cluster of Microbots, leaving them to face slow and painful deaths. However, unknown to Callaghan, some of the Microbots are being sucked into the portal alongside Krei's building, giving Hiro an idea. After guiding his teammates to safety, Hiro gives the command to take out the Microbots; once broken apart, they will be sucked into the portal, thus leaving Callaghan with no source power. The plan is set in motion once Honey and Fred create a smokescreen surrounding the bottom half of Callaghan's Microbot tower, to cover up their actions, while Hiro and Baymax distract the villain from above. According to plan, Callaghan is oblivious to the actions of Honey, Wasabi, Go Go, and Fred, and his army of bots continues to decline as his focus and frustration are aimed entirely on Hiro and Baymax. Before long, the boy and his robot are both captured, and Callaghan prepares to make the killing strike, only to find that he has run out of the remaining Microbots, thus rendering him powerless and vulnerable. With their plan having succeeded, Hiro and Baymax break free of their confinement and thrust towards the masked villain. Callaghan fearfully prepares for his supposedly oncoming demise, but instead of killing him, Hiro makes the decision to spare his life, explaining that he and Baymax refuse to harm a human being. Nevertheless, Baymax destroys Callaghan's mask, thus eliminating his remaining Microbots and descending the portal.

Callaghan's Arrest

An apprehended and regretful Callaghan watches as Abigail is taken away from him, once again.

However, as a result of the battle, the destruction causes the portal to become unstable, and on the verge of exploding, prompting everyone to flee. Baymax, however, stays behind, sensing life within the portal, and revealing the victim to be a female in hyper-sleep. Hiro correctly deduces it to be Abigail and makes the decision to journey inside the mysterious void, alongside Baymax, to rescue her. Meanwhile, Callaghan stays behind (while being physically restricted by Fred) with the team members and Krei, awaiting Abigail's return as the destabilized portal continues to break apart. Hiro manages to bring Abigail to safety, and police and paramedics soon arrive onto the scene. A now conscious Abigail is wheeled towards a waiting ambulance, ignorant to the events or her father's actions and presence, while the police apprehend Callaghan for his crimes and shove him into the back of a patrol car. Before being taken into custody, Callaghan manages to see his daughter one last time from a distance, and subsequently hangs his head down, possibly out of remorse for his actions.

Tv Show[]

in the animated series taking place directly after the film, Callaghan was referenced and mentioned by name in "Baymax Returns". He made his first, physical appearance in the episode "Mini-Max", where it is shown that he now resides in solitary confinement within a maximum security prison. Hiro visits Callaghan while researching information about Professor Granville, one of Callaghan's former coworkers. Callaghan explains that Granville resigned after an accident occurred on school grounds, supposedly on her account. Before Hiro takes his leave, Callaghan thanks him for saving Abigail. Callaghan then apologizes for what happened to Tadashi, and with a heavy heart, takes full responsibility for his death. Despite Callaghan's sentiment, Hiro is unable to forgive him.

Video games[]

Disney INFINITY: 3.0 Edition[]

Yokai makes an appearance in the San Fransokyo circuit of the Toy Box Speedway feature, as a non-playable character. After the first lap, the Microbots begin attacking and taking control over the city, eventually revealing the Silent Sparrow portal looming over the city, as well as Yokai, who ominously watches as the racers pass by while standing atop a towering cluster of Microbots.


Here we push the boundaries of robotics.

No. I used your microbots.

Give me the mask Hiro!

That was his mistake!

A setback?! You think my daughter is a setback?!

Now watch as all your technology gets destroyed, then it's your turn.

Abigail is gone!

I want my daughter back!

This ends now!

Abigail. (Last Words)



  • As shown in the film, Hiro's brother Tadashi, was intentionally lied to and murdered by Callaghan/Yokai.
  • He is based off of Lord Deathstrike from the original Big Hero 6 comic books.
  • Yokai's name means "spirit" in Japanese.
  • He is similar to Turbo from Wreck-It Ralph being disguised as King Candy.