The series uses elements from both the film & the original comic book series.
The series continues on the lives of Hiro Hamada & his robot pal Baymax, along with his team, the Big Hero 6, as they defend their hometown San Fransokyo from the silent yet notorious Yokai, as well as new bad guys, such as the malevolent Everwraith & X the Unknowable.
- Hiro Hamada (TBA): Founder & leader of the Big Hero 6, this robotics prodigy has the mind of a genius--& the heart of a 14-year-old.
- Baymax (TBA): Hiro's robotic synthformer. Baymax cares. That's what he was designed to do. But with a little help from Hiro, he can become more than he was built for. In the series, Baymax can now morph between his "mecha mode" & his newly upgraded "dragon mode".
- Ethel "GoGo" Tomago (TBA): A skilled motorcyclist & an accomplished racer & stunts-girl. She knows what it takes to be fast. She's tough, athletic, & loyal to the bone, but not much of a conversationalist.
- Aaron "Wasabi" Mallow (TBA): He's super smart & just a touch neurotic, but the big & burly neatnik can't help but join the cause when Hiro needs him most.
- Amanda "Honey Lemon" Ayers (TBA): A chemistry whiz, Honey may be as sweet as her namesake, but she has fire in her belly & a can-do attitude that makes her pretty much unstoppable. In battle, she carries a special Power Purse that contains a series of chem-balls, some of which contain miniature, artificial, inter-universe wormholes, granting her limited access to an indeterminate number of worlds & dimensions.
- Frederick "Fred" Ayno (TBA): This sign-twirling, monster loving, comic-book aficionado is sure to go places--when he's good & ready. In battle, he inhabits a huge, tentacled, fire-breathing "Fredzilla" creature suit that's piloted from one of its three eyes & is complete with claws, integrated communications, & a super bounce, as well as new other creature suits each based on famous Japanese kaiju, such as Mothra & Gamera.
- Kioshi Keishicho/Ebon Samurai (TBA): A mysterious samurai wielding a demonic katana. Not much is known about him at this time, except he's rivals with Silver Samurai for some apparent reason.
- Keniuchio Harada/Silver Samurai (TBA): A mutant samurai with the power to charge almost anything, most notably his katana, with mutant energy (described as a tachyon field) which enables it to slice through any known substance excluding adamantium. He also sports a suit of traditional samurai armor that's made of a silver metal, hence his professional name.
- Shiro Yoshida/Sunfire (TBA): A temperamental & arrogant mutant superhero who can generate superheated plasma & fly.
- Lumina/Sunpyre (TBA): The princess of the planet Coronar; Lumina bears resemblance to Shiro's deceased sister Leyu, the original Sunpyre. Sunpyre has powers similar to those of Sunfire, & although she may or may not be Shiro's actual sister, she helps him in times of need. She is best friends with Honey Lemon.
- Stephen Strange/Doctor Strange (voiced by Jack Coleman)
- Jonathan Hart/Jack of Hearts (TBA)
- Aaron Stack/Machine Man (TBA)
- Namor McKenzie (Sub-Mariner) (TBA): The half-human & half-Atlantean prince of Atlantis & enemy of Attuma.
- Sleepwalker (TBA)
- Howling Commandos
- Manphibian (TBA):
- Kishi Oramosha/Deadline (TBA): A notorious criminal that is on San Fransokyo's most wanted list & Mr. Yama's boss.
- Mr. Yama (TBA): The undisputed bot-fighter champion in San Fransokyo's underground bot fights with his prize robot, Little Yama.
- Kamikaze: Members of Mr. Yama's gang, a group of rocket-powered bomber men, attacking in a way that's almost suicidal.
- Jun Tenta/Sumo (TBA): A sumo wrestler working for Mr. Yama.
- The Fujitas: Mr. Yama's henchmen, a group of martial artist roller women in traditional Japanese wear and makeup.
- Everwraith (TBA): An astral embodiment of the negatives emotions of mankind.
- X the Unknowable (TBA): A disembodied creature who is able to transform its atomic structure at will, allowing it to assume any shape & size.
- Amatsu-Mikaboshi (TBA): A demonic god of evil who possessed the conventional abilities of one of the Kami, the order of Japanese deities, such as superhuman strength, speed, durability, agility, endurance, & recuperative abilities, as well as high ability to wield some form of potent Japanese dark magic. He is based on the Mikaboshi of Japanese mythology & the god of the Japanese race known as the Yomi, & speaks only in haiku.
- Professor Robert Callaghan/Yokai (TBA): A silent masked man with telepathic control over an army of Microbots. He was formerly head of the robotics program at San Fransokyo Institute of Technology who was responsible for the presumed death of Tadashi Hamada.
- Kuro (TBA): A silent & mysterious bionic ninja assassin serving under Deadline. His true identity is unknown, but when it's revealed, it will shock Hiro & the rest of Big Hero 6.
- Yandroth (TBA): Self-proclaimed "Scientist Supreme", an alien humanoid scientist who's been fighting against Doctor Strange.
- Badgal (TBA): A demonic-looking criminal.
- Brute (TBA): A personality construct used by the criminal Badgal. She can imprint "Brute" onto random civilians or heroes, giving them the personality & powers of her agent.
- Gunsmith (TBA):
- Whiplash (TBA):
- Horsemen of Apocalypse
- Orka (TBA): A strong (but relatively dim-witted) Atlantean soldier serving Attuma.
- Samuel Barone (Black Talon) (TBA): A voodoo cult leader who dresses up like a rooster.
- Mr. Ayno (voiced by Stan Lee): The father of Fred who has a secret life as a superhero. He often serves as the Big Hero 6's mentor & advisor.
- Cass Hamada (TBA): Hiro's aunt & guardian, who owns a popular San Fransokyo bakery & coffee shop.
- Mochi: The pet calico cat of the Hamada household.
- Alistair Krei (TBA): A pioneer entrepreneur & tech guru. Also one of the most distinguished alums of San Fransokyo Institute of Technology & owner of the biggest technology company in the world, Krei Tech. He & his company often assist Big Hero 6 by giving them their newest technology to fight crime.
- Professor Abigail Callaghan: The daughter of Robert Callaghan, the former head of the robotics program at San Fransokyo Institute of Technology, & former test pilot of Krei Technologies. Upon recovering from the hospital after being rescued by Hiro & Baymax, Abigail becomes the new head of the robotics program at San Fransokyo Institute of Technology.
- Otomo (TBA): A superhuman who assists the Big Hero 6.
- Amatsu-Kami: A race of superhumanly powerful humanoid beings who are after Mikaboshi, who is wanted for his betrayal.
- Amaterasu (TBA): The Japanese Goddess of the Sun.
- Bishamon (TBA): The Japanese God of war & happiness.
- Inari (TBA): The Japanese God of rice & prosperity, as well as the patron god of rice farmers.
- Izanagi (TBA): The leader of the Amatsu-Kami & Japanese God of the sky & sun.
- Kaminari (TBA): The Japanese Goddess of thunder & noise.
- Kumari (TBA): The Japanese Goddess of freshwater.
- Susanoo (TBA): The Japanese God of storms.
- Hotei (TBA): The Japanese God of drink & happiness.
- Tsukiyomi (TBA): The Japanese God of the Moon.
- Sergeant Gerson (TBA): A policeman.
- Furi Wamu (TBA): A secret agent who oversaw Big Hero 6's operations.
- Hiro to Zero