Antagonists
Main antagonists
- Shendu (voiced by James Sie) is the Demon Sorcerer of Fire and the main antagonist of the first two seasons, making recurring appearances thereafter. His Demon Portal is located at the entrance of Hong Kong Moose World and has the fire trigram: ☲. Centuries ago, Shendu was imprisoned in stone at the hands of Lo Pei and his twelve magical powers were sealed into the Talismans. He is briefly freed in the present day until being eventually turned back to stone and was destroyed. In his spirit form, Shendu accidentally possessed Valmont in an attempt to free the other Demon Sorcerers only to be banished back with a sword. Shendu was later resurrected by Daolon Wong only to be reduced to a statue again. In the series finale, Shendu is freed one last time to battle his son Drago, resulting in both being banished the Netherworld.
- The Dark Hand is a criminal syndicate led by Valmont that serves as a major antagonistic force against Jackie Chan and Section 13. It becomes defunct by the end of the second season.
- Shadowkhan are ninja-like shadow warriors who are initially summoned by Shendu. They are later revealed to be minions of the Oni, which each Oni General commanding its own distinct tribe of Shadowkhan (including Ninja, Razor, Bat, Sumo, Samurai, Squid, Crab, Mini, and Mantis). They are primarily summoned through their respective Oni Masks.
- Valmont (voiced by Julian Sands in seasons 1–2, Andrew Ableson in seasons 3–4, and Thomas Dekker as a child) is the ruthless crime lord in charge of the Dark Hand. He is a skilled fighter and acts as a secondary antagonist during the first two seasons but is reduced to a recurring character as he went broke for spending all his resources and wealth to fund expeditions to find the Talismans and Demon Portals. Valmont tried multiple times to regain his wealth before he gave up and became a bus driver in the series finale.
- Daolon Wong (voiced by James Hong) is a dark chi wizard and the main antagonist of season three. Described by Jade as the "Anti-Uncle", he is a powerful practitioner of dark magic and maintains a fierce rivalry with Uncle. He is initially introduced towards the end of season two as a minor recurring villain. He makes his last appearance in season four.
- Dark Chi Warriors are demonic servants created/transformed by Daolon Wong. When the original warriors are imprisoned, he converts the Dark Hand enforcers (Finn, Ratso, Chow, and later Hak Foo) into new ones.
- Tarakudo (voiced by Miguel Ferrer) is the Lord of all Oni and the main antagonist of season four. He seeks to collect the nine Oni Masks to free his generals and control the Shadowkhan. Like all Oni, he is susceptible to onions.
- Drago (voiced by Michael Rosenbaum) is Shendu's son from the future and the main antagonist of season five. Like his father, Drago is a demonic dragon endowed with fire demon chi. He harbors a grudge toward Jade because her adult self opposed him in his original timeline. He is introduced as a one-time villain in season four before becoming the main antagonist of season five. In the series finale, he and Shendu are both banished to the Netherworld.
Enforcers
The Enforcers are the henchmen of the Dark Hand. After season two, they are frequently employed by other villains, most notably Daolon Wong. A recurring theme is their repeated defeats by Jackie Chan. By season five, they become minor recurring characters with limited involvement in the main plot. At the end of the series, the four are completely reformed.
- Finn (voiced by Adam Baldwin) is the de-facto leader of the enforcers. He is an Irish-American with red hair and pasty-grey skin. As a Dark Chi Warrior, he replaces Ren. Before becoming a member of the Dark Hand, he sang in disco bands at weddings, as confirmed in the episode, "The Good Guys".
- Ratso (voiced by Clancy Brown) is another member of the group. He is denoted by his larger size and grayish-green skin tone. As a Dark Chi Warrior, he replaces Chui. Before joining the Dark Hand, Ratso studied theoretical physics, as confirmed in the episode, "The Good Guys".
- Chow (voiced by James Sie) is a Chinese-American member of group. He is denoted by his orange sunglasses and black leather jacket. As a Dark Chi Warrior, he replaces Gan. Before joining the Dark Hand, Chow worked at Sunglass Shack where he was Employee of the Month three times in a row, as confirmed in the episode, "The Good Guys".
- Hak Foo (voiced by Jim Cummings in season 1 and John DiMaggio from season 2 onward) is a muscular martial arts expert who announces his attacks using dramatic, metaphorical animal-themed names. He is first hired by Valmont and Shendu in season one and becomes a recurring antagonist after Tohru defects to the Chan side.
Ice Crew
The Ice Crew are a criminal group of teenage martial artists who serve Drago. They are initially introduced as one-time villains in season four before reappearing in season five where they replace the original enforcers. Drago transforms them into dragon hybrids with an aspect of his chi power.
- Strikemaster Ice (voiced by Mike Erwin) is the leader of the Ice Crew. He is nicknamed "crater face" by Jade due to his acne. Drago endows him with the power of dragon breath.
- MC Cobra (voiced by Jeff Fischer) is another member of the group. Drago endows him with the power of dragon speed.
- DJ Fist is the most heavily built member of the group and the only one never to speak. Drago endows him with the power of dragon strength.
Demon Sorcerers
The Demon Sorcerers are Shendu's siblings, ancient demons sealed in the Netherworld by the Eight Immortals centuries ago using the Pan'ku Box. Shendu attempts to free them in season two, but they are repeatedly banished back. Each of the Demon Sorcerers have a trigram and can only be banished back with the correct item that the Eight Immortals used. In season five, Drago tries to collect relics containing their chi.
- Po Kong (voiced by Mona Marshall) — The Mountain Demon with a ravenous appetite. Her portal is found within the courtyard of a castle on an island in Tokyo Bay, Japan and has the mountain trigram: ☶. She can only be banished back to the Demon Realm using a drum.
- Xiao Fung (voiced by Glenn Shadix) — The Wind Demon, a purple toad-like creature. His portal is located inside a washing machine at a prison in the Black Forest and has the wind trigram: ☴. He can only be banished back to the Demon Realm with a fan.
- Tchang Zu (voiced by Clancy Brown) — The Thunder Demon, an armored blue reptilian who controls lightning. His portal is a prop door found within the costume department of Mega-galactic Studios in Hollywood, California and has the thunder trigram: ☳. He can only be sent back to the Demon Realm with castanets.
- Tso Lan (voiced by Glenn Shadix) — The Moon Demon, a four-armed insectoid who can manipulate gravity. His portal is located high up in Earth's orbit and has the moon trigram: ☵. He can only be banished back to the Demon Realm with a lotus.
- Dai Gui (voiced by Frank Welker) — The Earth Demon, a large minotaur/lion-like creature with immense strength. His portal is located outside an abandoned villa in the countryside of Pamplona, Spain and has the earth trigram: ☷. He can only be banished back to the Demon Realm with a flower.
- Hsi Wu (voiced by André Sogliuzzo) — The Sky Demon, a gremlin-like bat-winged demon. His portal is in front of a restroom at Fenway Park in Boston, Massachusetts and has the sky trigram: ☰. He can only be banished back to the Demon realm with a flute.
- Bai Tza (voiced by Mona Marshall) — The Water Demon, a mermaid-like creature who once ruled Atlantis. Her portal is found within the hypogeum of the Colosseum in Rome, Italy and has the water trigram: ☱. She can only be banished back to the Demon realm with a gourd.
Oni Generals
The Oni Generals are Tarakudo's underlings, each in command of a specific tribe of Shadowkhan. They were imprisoned by good chi wizards in ancient Japan and sealed within the Oni Masks. When all nine masks are conjoined together in the season four finale, the Oni Generals break free but are soon defeated and sealed within Tarakudo's mask.
- Ikazuki (voiced by Maurice LaMarche) is the leader of the Oni Generals and Tarakudo's second-in-command who can summon Samurai Shadowkhan.
- Rairakku - An Oni General who can summon Ninja Shadowkhan.
- Murasaki - An Oni General who can summon Razor Shadowkhan.
- Kiiro - An Oni General who can summon Bat Shadowkhan.
- Midori - An Oni General who can summon Sumo Shadowkhan.
- Orenji - An Oni General who can summon Squid Shadowkhan.
- Kuro - An Oni General who can summon Crab Shadowkhan.
- Mosugurīn - An Oni General who can summon Mini Shadowkhan.
- Aka - An Oni General who can summon Mantis Shadowkhan.
Minor antagonists
- Karl Nivor (voiced by Ron Perlman) is a billionaire who feeds on endangered animals and employs a personal chef named Boris.
- Gnome Kop (voiced by Brian Doyle-Murray) is an action figure brought to life by the power of the Rat Talisman. He terrorizes the city while searching for his archenemy, Turbo Troll.
- Yokonowa Crime Family is a crime family that targets the Kyoto Octopus. It is led by an unnamed boss (voiced by Clyde Kusatsu).
- John Smith (voiced by Dan Gilvezan) is a wealthy man who accompanies Jackie and Jade to the Lost City of the Muntabs in search of the secrets of longevity. His butler is Larson (voiced by Oliver Muirhead).
- Origami (voiced by Tim Dang), real name Kuniko Kasahara, is an art collector and master thief who can transform into various origami forms.
- The Monk (voiced by Tim Lounibos) is a monk who accompanies Jackie and Jade to the Lotus Temple to steal the Scroll of Hung-Chao. He later teams up with Vanessa Barone, Peter Bailey, Angus McCutcheon, and Haggis to target the Silver Iguana of Awramba.
- Dr. Ashby Necrosis (voiced by Charles Shaughnessy) is a criminal genius known as the "Kingpin of Techno-Crime". His henchman is Hoyle (voiced by Greg Ellis), who can telekinetically manipulate cards.
- Spring-heeled Jack (voiced by Corey Burton) is a troll who once terrorized towns before being petrified by Simeon Magus. After Jackie accidentally frees him, he searches the city for Magus's descendants before being defeated and re-petrified.
- Vanessa Barone (voiced by Lauren Wood) is a treasure hunter, mercenary, and thief who targets the Eye of Aurora, which grants the power of teleportation. She later teams up with Peter Bailey, Angus McCutcheon, Haggis, and the Monk to target the Silver Iguana of Awramba.
- Peter Bailey (voiced by Roger Scott) is a black marketeer and thief who poses as an Inuit shaman. He later joins Vanessa Barone, Angus McCutcheon, Haggis, and the Monk in targeting the Silver Iguana of Awramba.
- Mr. Jumba (voiced by Dan Castellaneta) is a museum curator who targets the Sutras of Raktajiba along with his accomplices in an attempt to drain the Ganges River and reach the treasures beneath it. His accomplices are Dr. Weber (voiced by Patrick Pinney) and Portia Martindale (voiced by Kat Cressida).
- Cardiff Zendo (voiced by Maurice LaMarche) is a Moroccan art collector, café owner, and crime boss who seeks to obtain the Cat of Khartoum, which causes those scratched by it to exhibit cat-like traits.
- Giles (voiced by Michael T. Weiss) is the leader of a gang of hijackers targeting the Golden Dragon. His gang includes Butch and Basil (both voiced by Bill Fagerbakke) and an unnamed safecracker (voiced by Nicholas Guest).
- Angus McCutcheon and Haggis (both voiced by Victor Brandt) are two Scottish treasure hunters who seek the treasure of the pirate Greenbeard. They later team up with Vanessa Barone, Peter Bailey, and the Monk to target the Silver Iguana of Awramba.
- The Gloves of Greenbeard are sentient gloves that compel their wearers to steal valuable items.
- The Brotherhood of Magisters is an ancient order of magic-users led by the Head Magister (voiced by Neil Ross). They attempt to use Stonehenge to level London but are arrested by Interpol after their plan fails. The other members are voiced by Jeff Bennett, Rob Paulsen, and Frank Welker.
- Kiang-Shi (voiced by George Cheung) is a chi-draining vampire that feeds on the life energy of its victims. The vampire is blind and cannot see until it has drained enough chi. Uncle is briefly turned into its thrall until Jade and Tohru return him to normal.
- The Monkey King (voiced by Bill Tanzer in "I'll Be a Monkey's Puppet" and Billy West in "Monkey a Go-Go") is a magical Sun Wukong puppet. Pulling the puppet's leg grants the Monkey King a physical form at the cost of transforming the leg-puller into a puppet themselves. He is characterized as a chaotic bringer of mischief.
- Bartholomew Chang (voiced by Tim Dang) is a corrupt Taiwanese businessman obsessed with collecting rare jade artifacts. He is a recurring foe of the J-Team and later escapes prison with help from the Chang Gang.
- Yip (voiced by Tim Dang) is a dark chi wizard who collaborates with Bartholomew Chang to create evil clones of the J-Team, dubbed the J-Clones.
- The Chang Gang are Bartholomew Chang's team of criminal henchmen established to rival the J-Team. They include Tommy Chung (voiced by Tim Dang), Helga Sorensen (voiced by Cynthia Songé), Bob "The Bopper" Halfcock (voiced by Clancy Brown), and Phillip Crane (voiced by Bill Tanzer).
- Michael Diaz (voiced by Clancy Brown) is a con artist who posed as a museum curator to target the Golden Squid.
- Mirror Spirits are four evil spirits trapped in a mirror who cause people to transform into their greatest fear.
- Iso (voiced by Sam Riegel) is a dark chi wizard and the future self of Jade's friend Jimmy, who went rogue after becoming Tohru's apprentice.