The Character Sheet for Yuureitou.
The protagonist of the story. A loser NEET who finds himself pulled into bizarre events trying to solve the mystery of the Ghost Tower after he's saved by a mysterious man named Tetsuo.
- Act of True Love: Taichi does this for Tetsuo when he reveals Tetsuo's birth name Rei can also be read as Akira, which is a masculine name. Other people might only read it as "Rei" because they think of Tetsuo as female, but Taichi can only read it as Akira, proving to Tetsuo that Taichi genuinely sees him and loves him as a man. Further, Taichi tells Tetsuo that together they can create a world where society will see people like Tetsuo as normal and will be able to understand him and judge him fairly.
- Action Survivor: He's nothing but a NEET that just happens to get involved in several murder cases and treasure hunts. While he starts out as pretty much helpless, Taichi eventually has to learn to survive and fight on his own.
- Adorkable: He's a socially awkward dork, which can result endearing and funny at times.
- Amateur Sleuth: One of the main points of the series is Taichi working with Tetsuo to solve the mysteries surrounding the Ghost Tower and find the treasure hidden inside the tower.
- Ambiguous Gender Identity: Taichi's gender identity becomes somewhat debatable over time. He clearly identifies as male at the start of the story, but after he's forced into crossdressing for a while, Taichi finds it rather comfortable and even likes having Tetsuo treating him like a woman. At the end of the series, he's still living as a man, but keeps crossdressing sometimes. By all accounts, Taichi could ultimately be considered genderfluid.
- Attractive Bent-Gender: Several men in the opium village find "Taiko" attractive. Although, Taichi blames it on that there aren't any pretty women around.
- Becoming the Mask: After Amano disguises himself as Tetsuo's wife to evade the police, he realizes how comforting crossdressing is and since he is in love with Tetsuo, begins to wonder if he actually wanted to be Tetsuo's crossdressing submissive husband.
- Classical Anti-Hero: He starts out as this, being a gutless, insecure loser NEET with no self-esteem who only joins Tetsuo in his investigation because he has nowhere else to go. He gets better thanks to Character Development and becomes closer to a Pragmatic Hero.
- Commonality Connection: He and Tetsuo quickly bond over their shared love for mystery and crime novels.
- Disguised in Drag: Taichi is forced to wear woman's clothes and pretend to be Tetsuo's wife while they escape from the police and leave the city.
- Distressed Dude: He often gets in trouble and it's up to Tetsuo to save him.
- Friendless Background: He had no friends before meeting Tetsuo.
- Genre Savvy: Being a fan of mystery novels usually helps him as he's trying to solve a mystery.
- Grew a Spine: Amano starts out as a cowardly loser who can't do anything by himself and just goes along with what others tell him to do. After his weak will and cowardice result in him getting manipulated by Marube and betraying Tetsuo, Taichi starts to make his own decisions and fight his own battles, going as far as to decide to start an entire movement to get people like Tetsuo and Yamashina to be accepted by society.
- Heterosexual Life-Partners: With Tetsuo... At least he tries to be. Subverted when they end up as an Official Couple at the end of the story.
- If It's You, It's Okay: He at first feels attracted to Tetsuo as a woman, but he eventually comes to completely accept him and love him for who he is. Taichi even states he doesn't want to be with a Tetsuo who has given up on being a man.
- Lady and Knight: A rare male/male version. He usually takes the role of the helpless damsel that must be protected by Tetsuo. This is more obvious when Taichi is Disguised in Drag and pretends to be Tetsuo's wife.
- Let Them Die Happy: When Yamashina sobs about Tetsuo's physical sex in his final moments, Taichi pretends to be Tetsuo and holds Yamashina against his chest, letting him die believing that Tetsuo is physically male.
- Living Lie Detector: He eventually becomes able to tell when Tetsuo is lying.
- Loser Protagonist: Taichi is a socially awkward NEET and a Hikikomori at the start. Even when he gets better he's always getting into trouble.
- Lovable Coward
- Mystery Magnet: As Tetsuo points out, wherever he and Taichi go, murder mysteries ensue.
- Nerd Glasses
- NEET: Originally. Noticeably the story takes place in The '50s, so he lacks stereotypical qualities liking constantly being glued to the internet or being anime/game obsessed (he does like mysteries and scifi, which is presented as niche and weird, though).
- Nice Guy: When you get past his social awkwardness, Taichi is a pretty decent and considerate guy.
- No Social Skills: Due to being a NEET, Taichi is very socially awkward and isn't used to interacting with others.
- Official Couple: He and Tetsuo/Akira become a couple at the end of the series.
- Only Friend: Tetsuo mentions that Amano was his first friend. Growing up he stood out and didn't get along much with the girls at his orphanage. As an adult, he was very aloof until allying with Amano.
- Parental Abandonment: He never knew his parents and was raised in an orphanage until his stepfather adopted him.
- Revenge: He soon gains the personal reason to kill Shibanmushi after the latter kills Hanazono.
- Sensitive Guy and Manly Man: The Sensitive Guy to Tetsuo's Manly Man. Taichi is an awkward Unlucky Everydude, commonly a Distressed Dude, is Hollywood Homely, spends a good part of the series Disguised in Drag and has Lovable Coward aspects. Tetsuo, on the other hand, is a confident, mysterious, and Bishōnen Byronic Hero. Taichi even notes how Tetsuo acts more manly than he does despite being assigned female at birth.
- Sobriquet Sex Switch: When Disguised in Drag, Taichi goes by "Taiko".
- Take Me Instead: When Tesla takes Tetsuo to use him as a sacrifice in an organ transplant surgery, Taichi begs Tesla to take him instead and release Tetsuo. It doesn't work, but Tetsuo appreciates the thought.
- Took a Level in Badass: Taichi goes from relying on Tetsuo at the slightest sign of danger to beating criminals in the head with a stick (while in drag, no less!). And later, he kills Shinbanmushi/Jinbabue completely on his own by shooting his mouth off and throwing him off a cliff.
- Uke: He's an Adorkable Unlucky Everydude in sharp contrast with the mysterious and confident Tetsuo and Taichi is also a Distressed Dude who usually needs Tetsuo to come and save him when he gets in trouble. It becomes even more noticeable when Taichi is Disguised in Drag and he finds himself liking the idea of being Tetsuo's crossdressing lover. Lampshaded when he imagines himself at the bottom if he ever gets to sleep with Tetsuo.
- Understanding Boyfriend: It takes him a while to understand what Tetsuo being transgender means, but eventually Taichi comes to fully accept Tetsuo's male identity and his feelings for him don't change in the least. He's also able to accept Tetsuo despite being well aware that Tetsuo killed his own adoptive mother and can sympathize with the circumstances that led Tetsuo to it.
- Unlucky Everydude: At the start, he's just a loser NEET, he has no relatives or friends, so far all the women he's fallen for haven't felt the same. Due to his bad luck, Taichi almost ends up getting murdered by Shinbanmushi and his saviour Tetsuo gets him involved against his will in the mystery of the Ghost Tower and burns his place so he has nowhere else to go.
- Unwitting Instigator of Doom: Because he wanted to talk more to the Intrepid Reporter Hanazono, he ended up telling her about the Ghost Tower and the murderer that hides there. Although he warned her to not go alone, she ends up going to investigate the tower on her own and gets killed by Shinbanmushi.
- Unwitting Pawn: Marube blackmails Taichi in order to get closer to Tetsuo.
- Wholesome Crossdresser: Is Disguised in Drag for several chapters, but later finds crossdressing comforting and continues to wear a dress.
A mysterious transgender man with a high interest in the Ghost Tower and its secrets. He ends up involving Amano in his investigation after he saves his life. It's later revealed that until two years ago, he lived as a woman named Reiko and was known for killing his adopted mom before supposedly dying himself.
- Alternate Character Reading: Tetsuo's real birth name, Rei, uses another kanji that also can sound like Akira, the name he uses post-chapter 75.
- Ambiguous Gender Identity: It's revealed to the reader from early on that Tetsuo was assigned female, but it isn't made clear that he's a trans man instead of a crossdresser until much later on.
- Anti-Hero: Tetsuo is not a bad person, but his methods tend to be very morally questionable and manipulative.
- Arranged Marriage: Tetsuo was arranged to marry a man named Shiro when he lived as a woman. He did like his fiance as a friend, but he could not fall in love with him.
- The Atoner: For a short time, he tries to atone for killing his adopted mother by forcing himself to live as a woman, just like she wanted. After hearing of the Brain Transplant Marube wants to perform with him, Tetsuo agrees not because he believes it will work, but to die and pay for what he did to his mother. Taichi convinces him to not do it and wait until both of them can create a world that can judge Tetsuo fairly to atone for his sins.
- Attractive Bent-Gender: Everyone seems to be attracted to Tetsuo, whether they perceive him as a beautiful maiden, as an attractive Bishōnen man, or as something in between. Most of the girls are attracted to him as a man, Shiro is attracted to him as a woman, Taichi is initially attracted to him as a woman but grows to be attracted to him as a man, Marube sees him as someone in between, and Yamashina is secretly attracted to him as a man but tries to point out the androgynous features of Tetsuo's body in order to appear less gay.
- Because You Were Nice to Me: He grows to deeply appreciate and eventually fall in love with Taichi because Taichi is the first person who offered him genuine friendship and loyalty. Foremost, Taichi also becomes the first and only one to completely accept and love Tetsuo as a man.
- Becoming the Mask: At first, Tetsuo was only pretending to be Taichi's friend so he could use him to get to the treasure and get Taichi's birth certificate in exchange for the money. Eventually, Tetsuo really came to consider Taichi his best and only friend after they go through so much together and Taichi accepts Tetsuo for who he is.
- Berserk Button: Tetsuo is normally calm and easy-going, but say or do something that reminds him of his trans issues and you better watch out.
- Bishōnen: Tetsuo is a very pretty young man.
- Blinding Bangs: He had this before transitioning.
- Broken Ace: Tetsuo is attractive, charming, and intelligent; pretty much everything Amano wishes to be. However, beneath all that he hides a ton of issues coming from his transgender identity and killing his adopted mother so he could live as a man.
- Broken Bird: Being transgender, Tetsuo has lived a life where he has been oppressed, isolated and rejected, as no one has been able to understand him and accept him for who he is. Shiro could see that Tetsuo always had the sad eyes of a trapped person.
- Byronic Hero: He's charismatic, smart, attractive, has no qualms with manipulating and killing people and frequently angsts over his past, killing his stepmother and his transgender identity.
- Cassandra Truth: When he outright tells Taichi that he's Reiko, the woman he's looking for, Taichi doesn't believe him because he still doesn't know that Tetsuo is a trans man. He only believes it when he finds out Tetsuo was designated female at birth.
- Chick Magnet: Tetsuo is very popular among the ladies and many women blush in his presence.
- Commonality Connection: Like Taichi, Tetsuo loves mystery and crime novels, which plays a big part in their bond.
- Consummate Liar: Tetsuo is a master at lying and making it sound believable. Taichi points out Tetsuo always sounds very confident when lying.
- Deuteragonist: The other main character of the story, with just as much screentime and development as Taichi.
- Faking the Dead: He faked his death after killing his mother in order to escape from the police and live as a man.
- Family Theme Naming: Tetsuo's birth name, Reiko is the kanji for zero, put together from the circle in his father's last name Marube and the circle in his mother's last name Wada. Tetsuo, however, rejects that name and chooses to be called Akira.
- Friendless Background: Growing up, Tetsuo could never make friends with the girls at his orphanage. Even after starting to live as a man, Tetsuo kept his distance from others and the few people who got close to him either left him or Tetsuo was forced to abandon them to keep them away from danger. Tetsuo admits Taichi is the first real friend he has ever had.
- Guile Hero: Tetsuo uses his smarts and charm to manipulate his opponents and achieve his objectives.
- Have You Tried Not Being a Monster?: Tetsuo is treated this way because he is trans. After coming out to Shiro as a man, Tetsuo offers Shiro eternal friendship in place of a relationship. Shiro cannot handle this and never accepts the fact that he is no longer able to be Tetsuo's suitor. When Shibanmushi confronts Tetsuo and asks Tetsuo to become his ally in the Chapter 40s, he tells Tetsuo that Shiro saw Tetsuo as a monster who offered him eternal friendship, and that only a monster could love and accept another monster.
- Heterosexual Life-Partners: With Taichi. Subverted as they end up in a romantic relationship at the end of the story.
- If It's You, It's Okay: Tetsuo makes clear several times he's not into guys, but he eventually develops feelings for Taichi, the first person to completely accept him as a man. He ends up in a romantic relationship with Taichi at the end of the story.
- I Just Want to Have Friends: Tetsuo really wishes to have friends. However, due to his complicated circumstances and transgender identity, he can't find someone who doesn't leave him out of fear and who accepts him for who he is until he meets Amano.
- Lady and Knight: A rare male/male version. He acts as the chivalrous knight that protects Taichi from any danger. Taichi finds himself oddly attracted to Tetsuo's manly chivalry.
- Let Them Die Happy: Right before Shiro dies, Tetsuo lies to him and tells him he also loved him and gives him a Last Kiss.
- Lust Object: Marube is specially fixated on sleeping with Tetsuo since he's the spitting image of Onatsu, the woman Marube loved.
- Matricide: He killed his adopted mom when he lived as Reiko. Turns out he wasn't the one who tied her to the clock, but Tetsuo still indirectly killed her by doing nothing to save her.
- Meaningful Rename: Tetsuo's chosen name post-chapter 75, Akira, means strong and commanding. Since this name uses another kanji that also can sound like Tetsuo's birth name Rei, Taichi tells Tetsuo "Akira" is his legitimate male name and he can bear it with pride.
- Mr. Fanservice: The manga never seems to get tired of showing off Tetsuo's body. There's also a lot of chapter covers that show Tetsuo naked or wearing sexy clothes.
- Murder by Inaction: This turns out to be the real way Tetsuo killed his adoptive mother. She was tied to the clock tower by Shinbanmushi, but since she'd abused Tetsuo for his transgender identity as a child, he simply stood and watched. Tetsuo himself makes no attempt to claim it wasn't murder, telling the cops he'd killed her and using it as a reason that Amano shouldn't be his friend.
- Mystery Magnet: He points out that wherever he and Taichi go, there occurs a murder mystery they must solve.
- No Periods, Period: Tetsuo uses his period to try and trick Taichi into believing he slept with Marube. Taichi sees right through the lie.
- Official Couple: He and Taichi become a couple at the end of the series.
- Old Friend, New Gender: A tragic version. Tetsuo was engaged to a man when he lived as a woman. He eventually told his fiance he could not marry him because he identified as male and he did not like men, but hoped they could be like brothers. His fiance was considerably confused and not soon afterwards Tetsuo killed his adopted mother and "died". When they meet again Tetsuo's fiance is horribly disfigured and does not know this. He doesn't know anything about Tetsuo transitioning or the incidents in the past. He still sees Tetsuo as a woman and Tetsuo keeps up the facade of romance until his fiance dies protecting him.
- Only Known by Their Nickname: "Tetsuo" is merely the name he chose to use when he met Amano. Reiko is the name those at the orphanage gave him, but he hates it because it's a girl's name. Then it's revealed his birth name is Rei, but since its kanji can be read as Akira, which is a male name, Taichi tells Tetsuo to use that as his legitimate name.
- Pragmatic Hero: Tetsuo has no qualms with resorting to manipulation, extortion and blackmail to achieve his goals.
- Red Herring: Tetsuo initially seems is set up as a suspect of Shibanmushi's true identity, but this is later proven wrong.
- Replacement Goldfish: Yamashina found Tetsuo attractive because he reminded him of his deceased childhood friend Takashi.
- Sarashi: He wears one to flatten his chest.
- Seme: Tetsuo is a cool and mysterious Byronic Hero, in contrast of the Adorkable Distressed Dude Taichi, who early on notes Tetsuo can be pretty scary at times. Tetsuo also has heavy Broken Ace elements and has a buttload of problems, though Taichi becoming his Only Friend helps. Lampshaded when Taichi imagines Tetsuo at the top if they were to sleep together.
- Sensitive Guy and Manly Man: The Manly Man to Taichi's Sensitive Guy. Tetsuo is handsome, well-dressed, and a reserved Guile Hero, while Taichi is Adorkable, Disguised in Drag for a chunk of the series and a Distressed Dude who usually needs Tetsuo to come and save him when he gets in trouble.
- Sharp-Dressed Man: He's always wearing a nice suit.
- Smoking Is Cool: He smokes, which helps to make him look like the badass Anti-Hero he is.
- Sobriquet Sex Switch: Tetsuo's birth name Rei can be read as Akira, which Taichi says should be his legitimate male name. Tetsuo starts to go by Akira after this.
- Strong Family Resemblance: He is the spitting image of his real mother Onatsu.
- Sudden Name Change: His name from when he lived as a woman was thought to be "Rika" by fans. It wasn't until near the end that fan translations changed it to its correct "Reiko".
- Suppressed Mammaries: Tetsuo binds his breasts with a chest-wrapping bandage.
- Sympathetic Murder Backstory: He killed his adopted mom when he lived as Reiko. However, it's hard to not sympathize to Tetsuo when he was abused by his mother who refused to accept him as a man and tried to force him to live and act as a woman.
- Transgender Fetishization: Tetsuo is a transgender man and he gets more Fanservice scenes than any character in the series, including the girls.
- Transgender: Tetsuo was designated female at birth, but identifies as male. Prior to transitioning, he lived as Reiko and he was never comfortable living as a woman and wished to be accepted and treated as a man.
- Trans Tribulations: A big part of Tetsuo's character is how him being a trans man has made his life miserable because of how everyone keeps rejecting him for it. Growing up, he felt ostrasized from others due to not being like the girls at his orphanage. Once he was adopted, his mother would always get into fights over him about his boyish behavior and explicit desire to be a man. It got to the point where she arranged a marriage for him, despite him not liking boys. Tetsuo ended up killing his mom, faking his suicide, and running off as a man. Tetsuo notes that he can't get a girlfriend because they all get upset when he comes out to them. He eventually finds happiness when he befriends and falls in love with Taichi, who sees and loves him as a man.
- You're Insane!: He says this to Marube and Doctor Tesla after they reveal they want to perform a Brain Transplant surgery between him and Marube.
A public prosecutor with high influence in politics who recently bought the Ghost Tower.
- Abusive Dad: Satoko is noticeably terrified of him and he keeps her under strict regulations. It's later told he's been molesting her. And let's not get into his outright disgusting treatment of his biological child Tetsuo.
- Ambiguous Gender Identity: Marube wants to become a woman, however it's vague if it's due to being trans or if it's an ill-placed obsession with his lost love mixed with his need to be young and beautiful. The fact Marube is a villainous foil to his actually trans man son, Tetsuo, blurs lines more. The manga leans heavily towards the latter interpretation, especially when comparing Marube to Tetsuo.
- Bad Guys Do the Dirty Work: Though Shibanmushi was initially taken out by Taichi, he makes a point of not finishing him off because he doesnt want to be the one to judge him. Marube takes the final shot instead, and drops his corpse out of the Ghost Tower.
- Broken Ace: He's got status, money, good looks and everything a man could wish for. He's also a goddamn pervert and a Manipulative Bastard who isn't satisfied with what he has and just wants to achieve eternal beauty.
- Creepy Crossdresser: He dresses up like his late wife in the final arc. It's very disturbing.
- Crotch-Grab Sex Check: Marube overhears Tetsuo talking to Taichi about his body earlier and questions him. Tetsuo tells him he meant he has a micropenis. Marube does the crotch grab to check and (obviously) doesn't feel anything. Tetsuo keeps to his statement and says he's just small.
- Depraved Bisexual: He harasses Satoko, Amano, and Tetsuo because he is attracted to them and gets off on it.
- Dirty Old Man: He's nearing middle aged and is most definitely the most perverted and depraved character in the cast.
- Even Evil Has Standards: According to Yamashina, Marube despises rapists and he always makes sure they receive a harsh sentence. Later subverted when Marube tries to rape Taichi himself.
- Familial Body Snatcher: Marube wants to become this by having a Brain Transplant with his own descendants over and over again to keep eternally swapping bodies and forever live on in a body with the blood of him and Onatsu.
- Hypocrite: He gives harsh sentences to rapists, but he still tries to rape Taichi to break his spirit and have Akira/Rei for himself.
- I Just Want to Be Beautiful: He's obsessed with the concept of beauty and he works out to look good for his age. He will do anything to accomplish the ideal beauty he desires, even ask for a risky Brain Transplant with Tetsuo to get his beautiful body.
- I Just Want to Be You: Taken to the creepiest extreme possible. He wants to have a Brain Transplant with Tetsuo because he wants have the body and beauty of Onatsu, even if it's only for one day.
- I Love the Dead: Shown to be attached to his late wife's bones.
- Immortality Seeker: Marube has the intention of having children with his offspring and eternally swapping bodies with them so he can remain young and beautiful forever and at the same time create a twisted "eternal love" by living on in a body with the blood of him and his lost love Onatsu.
- The Jail Bait Wait: Marube makes it clear he is waiting for Satoko to turn twenty so he can rape her.
- Lecherous Licking: He does this to Tetsuo's fingers after saying he'd like to sleep with him much to Tetsuo's disgust.
- Likes Older Women: The love of his life was at least 10 years older than him. And he fell in love with her when he was 14.
- Love at First Sight: He fell in love with Tetsuo's real mother Onatsu the moment he first saw her.
- Love Father, Love Son: Deconstructed. He was in love with Tetsuo's real mother Onatsu and now lusts after Tetsuo because of his resemblance to her. The problem is Tetsuo is also his child.
- Love Makes You Crazy: Dear God... Marube was in love with Tetsuo's real mother Onatsu. Now, he lusts after his biological child Tetsuo because of his great resemblance to her. Later we find out he wants to have a Brain Transplant with Tetsuo so he can "become" Onatsu and have sex with his own body. Not only that, if the surgery succeeds he plans to have a child with Tetsuo so he can switch brains with his own children over and over again and thus create an "eternal love" with Onatsu by forever living on in a body with both her and his blood.
- Luke, I Am Your Father: He is revealed to be Tetsuo's biological father.
- Luke, I Might Be Your Father: When he takes Satoko to meet her mother Urako "Fuhenboku" Sakai, Urako tells Satoko that Marube might not be her real father and Marube was aware of it all along.
- Manipulative Bastard
- The Mourning After: He has never stopped loving Onatsu even years after her death. It gets very creepy when we see him getting touchy-feely with Onatsu's corpse. And even worse when it's revealed Marube intends to carry on his and Onatsu's love with Tetsuo, their child.
- Never Found the Body: The last time anyone sees him, he's lying with the corpse of Onatsu in the Ghost Tower. He was never heard from again, and no one's found anything of him.
- No Sense of Personal Space: He has the tendency to get way too disturbingly touchy-feely with people, even his own daughter.
- Older Than He Looks: Downplayed but he looks pretty young for someone nearing middle aged. He works out.
- One True Love: At his core, he believes Onatsu to be this. So much, that he planned on eternally swapping bodies and having children with his offspring simply because they had the blood of him and Onatsu in them, as a twisted testament to the love that they shared. However, at the end of the story Tetsuo and Taichi treat the pair as this, as they're just one of many versions of the protagonists of "The Ghost Tower" tale.
- Overprotective Dad: He doesn't like that Satoko makes male friends and once he accepts to hire Amano as his employee, he warns him to stay away from his daughter. He's also a creepy version of the trope, since he's trying to keep men away from Satoko because he wants her virginity for himself.
- Parental Incest: He has molested his daughter Satoko. However, they are not related by blood. Later, he tries to seduce Tetsuo, who is revealed to be his long lost child.
- Politically Incorrect Villain
- Pragmatic Villainy: He doesn't want to kill anyone, but not because of moral standards. He knows killing someone changes you and he doesn't want to change since he would stop being the same man he was when he met Onatsu.
- The Vamp: He plans to seduce Tetsuo and break his will.
- Villainous Crush: He has a sinister attraction to multiple characters, including the protagonists Tetsuo and Taichi. The former is actually his long-lost son, and he knows this.
- Villainous Incest: Marube is way too touchy-feely with his daughter Satoko. He also lusts after and tries to seduce Tetsuo, his long lost child.
- Wife Husbandry: He admits to Tetsuo that he raised Satoko so he could "share her maidenhood" and he was planning to take her virginity once she turned 20.
- Yandere: He's not above trying to rape Taichi if it means Tetsuo will return to him.
- You Got Spunk: Marube likes how Tetsuo tries to fight back against his seductions and he looks forward to break his will.
- Action Survivor: During the final battle, she is forced to pick up a gun to defend herself and help in the escape of the group from Marube and Tesla's Ghost Tower.
- Extreme Doormat: She does whatever her controlling father says and she doesn't have the will to stand against anyone on her own. She gets better later.
- Grew a Spine: Starts off as a submissive and delicate rich girl. In the final chapters, Satoko shows to have grown some backbone and has become a lot more bold.
- Heroic Bastard: She's the illegitimate child of Urako Sakai. Marube adopted her to use her to blackmail Sakai later on.
- I Just Want to Be Free: After living obediently under her father's thumb for most of her life, she wanted nothing more than to break out of his grasp. Circumstances force her to rationalize how free she wants to be and how she wants to live her life.
- Official Couple: With Harada.
- Ojou: She grew up as the daughter of a very well-off household and was raised as a spoiled rich lady.
- Rape as Backstory: She has been molested by her father Marube.
- Rescue Romance: She ends up with Harada, the police officer who saved her from Shinbanmushi in the underground maze and who later saves her from getting her legs broken by Marube's and Tesla's subordinates.
- Took a Level in Badass: Satoko goes from a defenseless, spoiled rich girl who completely depends on others to protect her to punching out some thugs that wanted to rob her and Amano and later, grabbing a gun to defend herself in the final battle.
The murderer at the Ghost Tower.
- An Arm and a Leg: He lost his arms and legs after Taichi threw him off a cliff.
- And I Must Scream: Turns out he didn't die when Taichi shot him and threw him off a cliff. Tesla found him and now has him in life support as a mummified mess without mouth, arms and legs that is in so much pain that not even morphine will work on him. Tesla has the intention to keep him like that for years. However, Marube ends up being the one to put him out of his misery.
- Big Bad: Shinbanmushi is the main villain for most of the series and finding out his real identity is one of the main mysteries of the story.
- The Dog Was the Mastermind: Shinbanmushi turns out to be no other than Jinbabue, Yamashina's bumbling commanding officer.
- He Who Must Not Be Seen: When his face is unmasked, his face is always drawn in black until the final reveal.
- Malevolent Masked Man: He always appears wearing a very terrifying mask.
- Not So Different: He tries to convince Tetsuo that they are both monsters that no one can accept or understand and they only can sympathize with each other.
- We Can Rule Together: He offers Tetsuo to join him, as Shinbanmushi claims they are both monsters that only can sympathize with each other. Tetsuo rejects him.
- Well-Intentioned Extremist: According to Marube, Shinbanmushi's motivation for seeking the Ghost Tower's treasure and murdering anyone that got in his way was to open an orphanage.
- Would Hit a Girl: He has no qualms about attacking and killing women.
- Would Hurt a Child: He kidnaps and tortures a little boy at one point in an attempt to lure Shirou out.
A policeman that befriends Taichi and Tetsuo.
- Ambiguous Situation: After the main plot wrapped up and some time had passed, one of the police officers had seen a man with Yamashina's face but didn't recognize the officer. Yamashina's body was intended for a brain transplant before the Ghost Tower disappeared, so Taichi raised the possibility that this could have happened. He also points out that Yamashina might not have died after all and instead suffered brain damage from the gunshot. But since the story ended not long after this revelation, we'll never know for sure.
- Died in Your Arms Tonight: Pretending to be Tetsuo, Taichi holds Yamashina in his arms as he dies.
- Friend on the Force: He befriends Taichi and Tetsuo and helps them out several times throughout the manga.
- Have I Mentioned I Am Heterosexual Today?: Yamashina often drops hints of how he finds men's physique attractive, only to deny he's gay right away.
- He-Man Woman Hater: He finds women disgusting and he can't stand one getting near him.
- Loving a Shadow: He feels attracted to Tetsuo because he reminds him of his childhood friend Takashi.
- Never Found the Body: After getting shot in the head by Shinbanmushi, Yamashina is assumed to be dead and Tesla retrieves his body. After Taichi, Tetsuo and co. escape from the Ghost Tower, the entire place along with Yamashina's body are never found. The final chapter heavily implies Yamashina is still alive, but lost his memory due to his brain injury.
- Red Herring: After Marube reveals Shinbanmushi is a police officer, everything seems to point out that Yamashina is the culprit, until the real Shinbanmushi appears and kills Yamashina. Shinbanmushi then is revealed to be Yamashina's commanding officer Jinbabue.
- Straight Gay
- Tragic Bromance: When he was a child, he had a friend named Takashi that Yamashina saw as "the main character of his life". One stormy night, Yamashina saw Takashi getting killed by a man named Tanaka and the criminal got away with it. Yamashina joined the police to one day get the chance to arrest and imprison Tanaka.
- Transparent Closet: While he repeatedly denies he's into men, he usually comments on how he finds men's physique more attractive than women's.
Tetsuo's ex-fiance from when he was Reiko. He went missing two years ago.
- Arranged Marriage: He was Tetsuo's arranged fiance by his stepmother. While he did love Tetsuo as a woman, Tetsuo only saw him as a friend and wanted him to treat him like a man.
- Dying Declaration of Love: He tells Tetsuo that he loves him before dying. Tetsuo tells him he loved him too.
- Facial Horror: His face was horribly disfigured after Shinbanmushi tried to burn him to death.
- He Knows Too Much: Shinbanmushi kills him before Shiro can regain his memories of who burned his face and reveal Shinbanmushi's identity.
- Hopeless Suitor: He really loved Tetsuo and wanted to marry him, but due to being transgender Tetsuo could only think of him as a good friend.
- Incompatible Orientation: He really loved his fiancee, but Tetsuo couldn't reciprocate his feelings because Tetsuo was transgender and couldn't love a man.
- Irony: He left Tetsuo because he told him he could never love another man. While Tetsuo initially only offered him friendship, if Shirou had at least tried to accept Tetsuo as a man, it's possible Tetsuo could have fallen in love with him in the same way he fell in love with Taichi when the latter accepted him.
- I Was Quite a Looker: He was a quite handsome man until Shinbanmushi tried to burn him to death and horribly disfigured his face.
- Love at First Sight: He fell in love with Tetsuo when he lived as Reiko the moment he first met him.
- Not with Them for the Money: He admits that he at first wanted to get close to Tetsuo to get his family fortune, but after he met him he fell in love with him for real and completely forgot about the money.
- Purely Aesthetic Glasses: He has good eyesight, but he wore glasses because he pretended to have astigmatism so he wouldn't have to become a soldier and fight at the war.
- Taking You with Me: He tries to kill Shinbanmushi along with him. He fails.
- Trauma-Induced Amnesia: His memories got messed up as a result of the trauma of getting his face horribly disfigured.
A doctor who runs an unlicensed research facility.
- Back-Alley Doctor: He runs an unlicensed research facility and is not above using a human for experimental organ transplant surgeries.
- Blue and Orange Morality: He claims to see all life as precious and he wants to save as many as possible. Still, he thinks is okay to use the organs of corpses for his experiments, resort to human experimentation on people that he considers beyond saving and keep in life support someone that is horribly mutilated and in constant pain in order to "protect his life".
- But Not Too Foreign: He has western blood in him.
- Loss of Identity: His grandfather messed with his face since he was very young so Tesla can't even remember how his face originally looked like. He can't think of his current face as his own, which is why he always wears a mask to feel at ease.
- Mad Doctor: Tesla honestly values human life and wants to use medicine to save others, but he's also quite unhinged and morally grey about his methods.
- Morally Ambiguous Doctorate: Tesla claims to be a doctor who only wants to save as many lives as possible, but his methods are very morally questionable at best.
- The Needs of the Many: He measures the value of life by numbers. He's willing to sacrifice one life to save three and later he cancels the organ transplant surgery and lets Tetsuo go because Tetsuo claimed he placed bombs that would kill hundreds of people unless Tesla releases him.
- Totalitarian Utilitarian: His goal is to improve medicine and save as many lives as possible. However, he believes The Needs of the Many outweigh the needs of the few, so he's willing to sacrifice some humans for experimental organ transplant surgeries.
- Well-Intentioned Extremist: He wants to save as many lives as possible and to do that he's willing to kidnap Taichi, Tetsuo and Yamashina, inject them with a deadly virus and force them to choose a human sacrifice for Tesla's experimental organ transplant surgery in order to save three people.
- Younger Than He Looks: He looks like an old man, but it's soon revealed he's wearing a mask. When Tetsuo forces him to reveal his face, Tesla is revealed to be a handsome young man.
Doctor Tesla's assistant.
- Facial Horror: When Tetsuo forces her to take her mask off, Q's real face looks like a skeleton. It's eventually revealed her face was horribly disfigured after she tried plastic surgery on herself and she had her face surgically cut off.
- I Was Quite a Looker: She was actually a pretty attractive woman before she ruined her face when she tried plastic surgery on herself in an attempt to look prettier.
- One-Letter Name: She only goes by "Q". This is what allows Taichi to deduce Q must be Satomi Hisae. Tesla's father once compared Satomi's disfigured face to a monster named kudan. The "ku" in kudan is pronounced as "que" in French.
- Only Known by Their Nickname: Her real name is Satomi Hisae. It seems she decided to call herself "Q" in reference to the "kudan", a monster she was compared to after her face got horribly disfigured.
Urako "Fuhenboku" Sakai
A detective novelist residing in Tokyo. Taichi and Tetsuo go look for her after realizing one of her novels contains a maze similar to that under the Ghost Tower mansion.
- Dirty Communists: She was part of a Communist group when she was younger and it's implied she was the one who killed Onatsu, Tetsuo's biological mother, to get the key to the treasure.
- Missing Mom: She's Satoko's long lost mother. When Satoko was born, Urako was part of a communist party and she had to abandon Satoko so her daughter wouldn't be affected by it.
- Pen Name: Her real name is Urako Sakai, Fuhenboku Sakai is a name she uses to publish her novels and to hide her connection to the communists.
- Samus Is a Girl: It isn't revealed that Fuhenboku Sakai is a woman until she's introduced.
- Who's Your Daddy?: She admits that she is not sure of who is Satoko's real father since she slept around a lot.
- Write What You Know: In-Universe example. She says her novel The Gray Maze is based on a fairy tale that she heard long ago.
A police officer who takes part in the investigation of the underground labyrinth of the Ghost Tower mansion after Shinbanmushi kidnaps a child.
- An Arm and a Leg: He gets his right arm cut off by Shinbanmushi.
- Arm Cannon: He has his right arm replaced by a Gatling gun.
- Chekhov's Gunman: After being left to an unknown fate in his fight with Shinbanmushi, he disappears for around 50 chapters before coming back in the final arc as one of Tesla's subordinates and playing an important part in the climax by helping Satoko and Maruyama escape.
- Handicapped Badass: Losing his right arm didn't made him any less badass. He still can take down several men all by himself.
- Official Couple: With Satoko.