The Demon Card or Shadow Guard in the English dub is the most powerful organization of evil and darkness in the world, who uses the power of the evil magical stones Dark Bring to perform their sinister deeds. It was originally founded by Gale Raregroove and Gale Glory, and is called Demon Card because Glory spelled the sign wrongly (he meant it as Demon Guard). After the membership grew too large for the two to support, Raregroove started accepting more unsavory tasks such as assassination thus leading to the departure of Glory. This incarnation was later wiped out by the empire after Glory heard they were using Dark Bring and informed the Empire of their location. Raregroove survived to rebuild the second incarnation of Demon Card. In many ways, they can be considered the successor to the once-powerful kingdom of the Raregrooves, who once tried to subjugate the world in the same manner. Then, King Raregroove's son, Lucia Raregroove took over Demon Card and became their strongest leader.
Commander in Chief
The protectors of the two generations of Commander in Chief of Demon Card as well as being non-humans of unparalled strength.
- Guardians of the Gate - These five warriors from other dimensions are brought together by one of King's Dark Brings, the Gate. They are all powerful. They only oppose a threat to Haru and his friends in Volume 8. Like several villains leading up to them, all of their names are something in real life if you add "ma" to the beginning of the name, a play on the fact that they are all Majin ("Ma" meaning demon and "jin" denoting a person. Translated as "demonoid" in the English manga). It is assumed that other than the captain Ltiangle (who died at Musica's hand) and Let (who joined Haru's group) that the remaining three are still alive. Whether the remaining Guardians died in the collapse of the Tower of Din or managed to escape is not told in the story.
- Ltiangle - The leader and most powerful of the guardians, his Dark Bring is Transparent. It allows him to turn objects, himself included, invisible. This includes his weapons and some of the landscape around his opponent. His weapon is probably some kind of long blade (you cannot tell what is is because it is invisible). He also has a power that is not connected to his Dark Bring, the ability to seal his opponents in the landscape of their memories while the guardians fight them. For instance, when Haru was in the psychic prison, he was on the shores of Garage Island. Ltiangle is defeated and killed by Musica. According to the author, he was the hardest character to draw in the entire series due to his armor and tower shaped head. "ma"ltiangle (multiangle)
- Let - He is the second most powerful Palace Guardian, but he was defeated by Haru. After Haru proved to Let that there is more to living and fighting than life and death, Let began to change his ways. He eventually became Haru's friend. In Volume 10, Let sort of suggests that he has become stronger than Ltiangle because he challenges Musica, and he said that his power and skills have greatly improved. "ma"let (mallet)
- Rionette - He is really tall, has a really long neck, and can only speak in rhyme. He is considered the most sadistic of the group. His Dark Bring is Shadow Doll. He can teleport himself from where he's standing to wherever the opponent's shadow is. Also, when he stands on that shadow, the opponent cannot move. He is easily distracted with random tricks, so defeating him isn't terribly hard. He was defeated by Plue, Griff, Salasido, Remmy, and Elie. "marionette" (marionette)
- Ron Glace - He is a huge, really not smart, suit of armor that speaks with bad grammar. He is actually the weakest member of the Palace Guardians. He carries a huge spear which he uses as a medium for his Dark Bring, Spikes. Whenever his spear plows into the ground, metal spikes come out of the ground. He was defeated by Musica and Salasido. "ma"ron glace (Marron glacé )
- Racas - This guy has hair in the shape of a horseshoe and carries two maracas. He cannot help dancing and his Dark Bring, Rhythm Counter, allows him to reflect an attack back that is a few times stronger. He can also read people's minds. He also is constantly seeking the approval of Ltiangle. After Haru used the Rune Save to clear his mind, Haru was able to defeat Racas. "ma"racas (maracas)
- Four Demon Gods- The four lords of the Demon World, they were all recruited by Lucia for Demon Card's DR (Dark Rendezvous) plan. In a way, these four are the incarnation of the original demon guard of King, both of which were used to delay the heroes.
- Uta - Also called "Uta the Eternal," he was used to defend Lucia as he prepared the second Overdrive. He was a human-like demon who possessed inhuman strength, wielding a hundred-foot longsword with incredible ease. He has a second form where 2 horns grow from his head, giving him increased combat abilities. Let managed to defeat him after reverted to his true form, the King of Dragon race known as Jaava Let Dahaaka and died in the process (revived by the Memories of Star later).
- Asura - A Demon God who was in possession of the final piece of the Sinclaire, also known as Asura of Darkness. While normally small and imp-like, it is merely to conceal his true form: a gargantuan Satanic demon with a countless amount of DB embedded into its body. He has the ability to use any DB in the world and also can combine DB to produce effects. Since his body is made of DB and DB can only be destroyed by Rave and Plue, he is impervious to all other forms of attacks. He was smashed into pieces by Haru.
- Megido - A massive humanoid lion, he was the first to join Lucia during the Dark Rendezvous recruiting process due to his desire to gain more power. He drives a flying coach, and breathes massive blasts of fire capable of damaging even Endless. He was defeated by Shuda due to Shuda's high resistance to fire. As he lies defeated, he breaks the ground so that Shuda would die with him as well, but Shuda is saved by Haru, similar to the time when Shuda had lost to Haru and Haru grabbed onto to his arm.
- Jiero - A Demon God resembling a scantily-clad woman, also known as Jiero of Despair, also said to be the former queen of the makai world . While human in appearance, she has great powers over ice. Initially frozen solid, she awoke from Sinclaire's presence and proceeded to freeze Punk Street though Musica manages to undo this when he creates a new sword for Haru. Her body is made of ice allowing her to regenerate herself, and she controls magic and despair which somewhat fuels. It took a combined effort of Julia, Belnika, and Niebel to defeat her (the latter weakening her and the former giving the final blow by breathing fire into her mouth destroying her skeleton), in which both Belnika and Niebel died due to the sustained damage (both also revived by the Memories of Star later). As the fight went on she surprised her opponents refused to give in, willing to die just to defeat her. In the end as Jiero crumbles to nothingness, she comments how she's the one who feels despair.
- Oracion Seis
- Imperial Guards-The Imperial Empire version of the 5 Palace Guardians (excluding a fifth member) for Deep Snow, they served him after the Empire's demise by Shadow Guard because they had nothing better to do. They are all killed (excluding Lazenby) in Vol. 19 by Shuda.
- The Leaders below the commander in chief and main enforcers (including Sieg Hart for a period of time) and are strongest next to the Guardian level Demon Card agents.
Basic commanders of smaller units or demonoids in King's service, at the time they possess decent strength that causes our heroes trouble in the beginning until they get stronger.
- Georco - President of the dog racing track in Hip Hop Town, Georco possesses the “shadow stone” Smoke Bay, enabling him to turn his body into smoke, and create a cloud of suffocating, carbon monoxide. Haru was almost defeated by him in volume 2, but he was much weaker then, and Georco got his butt kicked after Plue somehow managed to take his DB. In the manga, he is defeated the first Rave stone, but in the anime; it is the Ten Powers's first form. In the anime, it is hinted that Shuda had him killed after his defeat. Blood type: O.
- Lance - Commander of the 17th unit of Shadow Guard soldiers, he wields the Beast Sword, forged by Galein Musica. It allows him to create illusions at his will. His DB allows him to make his illusions real. Somewhat of a psychopath, he captured Elie and injured Hamrio Musica in volume 2, and was defeated by Haru in Volume 3. He was also responsible for killing off Musica's family. Blood type: A.
- Feber - Probably the weakest enemy ever mentioned by his name. He was the first Demon Card soldier Haru fought. He badly injured Shiba with a bazooka in Volume 1, but Haru punched him with the Rave and defeated him. Shuda later gave him the Dark Bring "Full Metal", which enabled him to turn his skin into metal. He went after Haru again, and was again defeated with the Explosion form of Ten Powers. It is possible Gemma later hired him in Cafe Tsubomi.
- Poosya - One of Shuda's followers, who shows an interest in Elie and in Reina. His Dark Bring, Glue Tear, can make glue from his hat. His "special attack" combines glue with Rugar's Delta Cannon giving the tip of his glue strands a sharp pointy edge which he can control at will. Blood type: B.
(voice)English: Dave Wittenberg (episodes 2,12,16-17) Steve Cassling (episodes 13-14)
- Rugar - A cyborg born in Hard Core, created by Demon Card. He hates to be insulted, and can use an attack called "Delta Cannon," which launches triangle-shaped projectiles from his hands. Like Poosya, he is a follower of Shuda, and gets defeated by Musica.
voice(English) : Lex Lang (episodes 13-14,18) Dave Wittenberg (episodes 2,12,16-17) Japanese: Shinichiro Miki
- Go - A member of Demon Card who is a movie director. He uses a Dark Bring that controls thunder. His weapon is a thunder hammer. He fights Haru and loses. He later returns to help Haru reach the star memory. Blood type: O.
- Rosa - Go's wife who uses a "Hunter Wolf" as a weapon which is a detachable sword that seeks their enemy. She fights Elie but loses. She loves her face a lot. She has a Dark Bring that makes men dance uncontrollably. She later convinces Go to help Haru reach the star memory. Blood type: B.