Koenma

Name: Koenma

Special Power: Pacifier

Anime Show: Ghost Fighter

Biography:

King Enma Jr., usually addressed as Koenma is the son of spirit realm ruler King Enma, and the one who takes responsibility of his father's work when he's away. Koenma usually appears as a toddler with a pacifier in his mouth, though he is said to be at least 700 years old. He can also transform into a young adult form, retaining his pacifier and the letters "Jr" on his forehead. Koenma acts as Yusuke's boss, assigning his cases. 

Keiko Yukimura

Name: Keiko Yukimura a.k.a Jenny

Special Power: Eugene love interest

Anime Show: Ghost Fighter

Biography:

Keiko Yukimura is Yusuke's childhood friend and classmate. She has known Yusuke for many years and acts as a parental figure, often trying to get him to attend his classes and behave, though usually to no avail. Yusuke attempts to keep his job as spirit detective a secret from Keiko though she finds out about it during his third case, as the Saint Beasts end up using her as bait to anger Yusuke.

Shigure

Name: Shigure

Special Power: Boomerang Circle

Anime Show: Ghost Fighter

Biography:

Shigure is a demon surgeon and Osteopath. As payment for his services, Shigure requires that his patient have an interesting life story. As well, he requires of them a part of that life, though in eccentric ways. While looking for his lost tear stone and the Ice Kingdom where he was born, Hiei approaches Shigure and hires him to implant the Evil Eye in his forehead.

Raizen

Name: Raizen

Special Power: Energy Blast

Anime Show: Ghost Fighter

Biography:

Raizen is one of the three kings of the Makai (in fact, he was considered the strongest of the three) and Yusuke's ancestor. 700 years before Yusuke is born, Raizen, then a young demon, comes to the human world looking for people to eat, and is massively injured in confrontations with human warriors. 

Mukuro

Name: Mukuro

Special Power: Telepathy

Anime Show: Ghost Fighter

Biography:

Mukuro is one of the three kings of the Makai realm. Early in her childhood, she is sold into slavery to a humanoid demon named Chikou. Her master is continuously cruel to her and used Mukuro as a sex slave. He raped her every year on her birthday. To control her, he implanted a single memory of himself being kind to her mind, which she remembered each time she thought of killing him. 

Yomi

Name: Yomi

Special Power: Tornado Energy Blast

Anime Show: Ghost Fighter

Biography:

Yomi is the newest of the Three Kings. He was second in command to Kurama's brigand prior to Kurama placing his soul into a mortal. Yomi, however, was reckless, losing countless men in unauthorized raids and direct confrontation, thinking it more exciting that way. Kurama, angered, sent an assassin to blind him as punishment. 

Sadao Makihara

Name: Sadao Makihara

Special Power: Territory is in his stomach

Anime Show: Ghost Fighter

Biography:

Sadao Makihara is a human who develops superhuman powers as a result of the demon plane hole opened by Sensui. He is able to eat other beings and gain their powers as his own. Sensui orders him to devour the regenerating head of Elder Toguro but the immortal demon ends up taking over Makihara's body.

Tsukihito Amanuma

Name: Tsukihito Amanuma

Special Power: Territory

Anime Show: Ghost Fighter

Biography:

Tsukihito Amanuma is a human who develops superhuman powers as a result of the demon plane hole opened by Sensui. He is rejected from kids his age because of his extreme love of video games since most kids play sports. Amanuma is able to bring video games to life, creating his territory within them. He along with Gourmet capture Kuwabara. 

Kiyoshi Mitarai

Name: Kiyoshi Mitarai

Special Power: Monster Summoner

Anime Show: Ghost Fighter

Biography:

Kiyoshi Mitarai is a human who develops superhuman powers as a result of the demon plane hole opened by Sensui. He is able to mix his blood with water to create water golems. His territory is contained within these monsters. Mitarai is emotionally scarred after watching the Chapter Black videotape. He also is fueled by his hatred of bullies since he never seemed to have any friends. 

Minoru Kamiya

Name: Minoru Kamiya

Special Power: Chemical Manipulation

Anime Show: Ghost Fighter

Biography:

Minoru a charismatic speaker who was in control during the beginning of the Sensui arc. He also uses his body with deadly precision and has also lost the sensation of pain, allowing him to reattach his own body parts with ease. Aside from his regenerative skill, Kamiya also has some medical knowledge.