- M1: An orange-haired teenage boy with a mop of orange hair that constantly covers his eyes, he can generate and throw razor-edged rings of energy called Angel Blades (Angel Chakram in the original Japanese version); three to each arm, two of which are illusions. His bangs almost always cover his eyes, but when his large eyes are revealed, they give him a rather feminine appearance. His actual name is Yen (円).
- M2: An older-looking man with a Mandarin type outfit, braided ponytail, and a mustache who can manifest a javelin made of Spirit Energy that is invisible with those of lower spiritual awareness, that can be surprisingly-lethal, as seen in his Invisible Slash (Swing Crush in the original Japanese version) technique. His design seems to be based on a Chinese martial artist, making him resemble Lau Chan From Virtua Fighter and Master Asia from Mobile Fighter G Gundam. His actual name is Ryo (魁).
- M3: A young man with brown hair and a scar above his right temple that can shape one of both of his hands into an energy bomb in order to deliver a palm thrust that can shatter the ground or strike the opponent's internal organs as seen with Kuwabara, called Grisly Claw (Hound Claw in the original Japanese version), with explosive results. He offers to join Team Urameshi to make up for his sins, but Yusuke turned him down, telling him to take care of his master. His actual name is Kai (梁).
- M4: An older leopard-lizard demon, killed in an instant by Kurama and Hiei in the forest outside of the stadium. He is the more impulsive of the two, and appears more human in the manga (while still having his tail), but reveals more demonic features as he is being decapitated.
- M5: A young tiger-lizard demon who commands the robot Gatasubal. He seems to be more intelligent than M4, preferring to control Gatsubaru rather than directly confront Hiei and Kurama. In the manga he has black hair and much more human features, but reveals his slit eyes, fangs, and tongue when he is annoyed. After the robot is defeated, he is tortured by Kurama and Hiei to reveal the location of Ichigaki's lab, and is cut into several pieces (despite Kurama's claim that they wouldn't kill him if he surrendered). In the anime, however, he is simply beaten up by Hiei; ultimately spared albeit knocked unconscious.
- Gatasubal: A cyborg demon. Called (Yokoju) Gatasubaru (ガタスバル, Gatasuval, translates to Spectral Steel Beast): in the original Japanese. Gatasubal was an early prototype designed by Dr. Ichigaki. It's entire body is covered with a hybrid metal combining steel with living cells. He prevented it from having the ability to feel any pain or fear. It attacks by extending its arms, which can actually stop and change direction in midair in order to track its target. Kurama manages to have one of its stretching arms hit its own body with force sufficient to crack it's bio-metal alloy shell (strong enough to block both the Rose Whip and Hiei's sword), thus allowing him to worm his Rose Whip into its innards, connecting it to the robot's circuits, gaining total control of the robot, and turning it against its master. Thus its inability to feel pain led to its downfall, as it would have recoiled had it been able to feel pain. After it was used to by Kurama and Hiei to enter the stadium by making a giant hole, it is never seen again.
The teacher of M1, M2, and M3, their father-figure Master Metamura, had fallen sick to some kind of illness. His students despaired when they learned that medical treatment would cost seventy-thousand.
Dr. Ichigaki appears and offers to cure Master Metamura for free, with the condition that he uses M1, M2, and M3 as subjects for his experiments.
At the Dark Tournament, where Kuwabara had a premonition about their predicament, Dr. Ichigaki makes things interesting by declaring that if Team Urameshi loses, they'll be his next subjects for experimentation (In the English anime, he only wants Yusuke for his experiments). When Genkai, in her role as the Masked Fighter, ups the ante with an offer of a six-person battle royale, Ichigaki gleefully accepts. When asked what's going on, she explains that she met Master Metamura and his students a long time ago and that what struck her about them was their acceptance of his philosophy of good character over physical prowess, which extends to his students having an enormous amount of respect for life and never killing no matter what.
It's what had unnerved Kuwabara so badly. His high Spirit Awareness was telling him that M1, M2 and M3 are watching their bodies kill as ordered by Dr. Ichigaki. It turns out that he had implanted a demonic nanotechnological organism called Virucchi, into their spines and bloodstreams, as a method of controlling them.
When Kurama and Hiei crash the match, they reveal that removing the Virucchi would kill M1, M2, and M3; and the fact that Dr. Ichigaki had caused Master Metamura's illness in the first place. Attempts at confronting Ichigaki suddenly has Kuwabara realizing that their consciousness had been set back, and Yusuke realizes that they're begging him to kill them.
Reluctantly complying, Yusuke charges up his Spirit Gun before Genkai intervenes and uses her Spirit Wave technique in order to purify the Virucchi and free M1, M2, and M3 of their control. With his team defeated, Dr. Ichigaki resorts to transforming himself with a mutagenic compound. But it doesn't work, as Yusuke demolishes the Doctor with six powerful punches.
Master Metamura, cured of his illness by Kurama, manages to make his way into the stadium and is reunited with his wayward students.
The students make more cameos in the audience, cheering for Team Urameshi (more in the manga). While Ryo grasps his chest in pain when Younger Toguro began stealing souls from the audience, ultimately the three of them survived to see Toguro defeated by Yusuke. Presumably they were able to successfully escape from the collapsing stadium as well.
- Dr. Ichigaki's team seems to be the only known team other than Team Uraotogi to be self-sponsored and not endorsed by a member of the Black Black Club or Spirit World, as the founding member is implied to the fundraiser of the team, with all the devices he can afford from calculators and robots to parasitic implants and implied demonic surgery on his fighters.