Mannish Boy is a dark-complected baby. He has large ears, and his most notable features are fang-like canines. Mannish Boy wears typical baby clothes, complete with shoes and a headscarf.
Mannish Boy is an impossible genius: although he is a baby, he has the mental capabilities of a grown man. In public, Mannish Boy hides his true self and acts like an ordinary baby to throw people off.
However, he will reveal his true self to his sleeping victims. Although he cannot speak yet and at best can chuckle an evil "hee hee hee", Mannish Boy has the intellect, vocabulary and behaviour of an adult and can express his true self through his Stand, Death Thirteen. As Kakyoin stated, this baby is able to see a scorpion, identify it as a threat, and use a pin to kill it before it attacks him. He is also quick-witted enough to hide said scorpion in his mouth as Kakyoin searches his crib for proofs. Mannish Boy is quite devious, using his appearance to fool the Joestar Group into bringing him with them. He is also exceptionally cruel and unhinged as he takes pleasure in playing with his helpless victims by submitting them to horrifying torments (e.g. covering Kakyoin with eyeballs to silence him) and humiliating them, and has no problem killing other humans and animals. He is extremely foul-mouthed and arrogant and looks down on the heroes, frequently insulting them in thoughts and rubbing in their powerlessness when he has them in his dreamworld. Mannish Boy also smokes.
- Main article: Death Thirteen
Mannish Boy's Stand is Death Thirteen, a clown-like Stand which can pull the consciousness of its sleeping victims into a dream-world where it has absolute control and where they cannot summon their Stands, then murder them with impunity.
Demonstrating physical skill also unusual for his age, Mannish Boy is dexterous enough to kill a scorpion with a safety pin. Moreover, he is unusually intelligent for his age, as he's able to speak and have coherent thoughts, despite being only a baby.
Sent by DIO to kill the Joestar Group, Mannish Boy manages to reach Yabrin at the same time as the heroes. He tries to assassinate Noriaki Kakyoin but only manages to kill a nearby dog caught in Death Thirteen's nightmare world before Kakyoin is woken up by Jean Pierre Polnareff. In the dream, Kakyoin's hand was cut by Death Thirteen's scythe and the wound carries over to the waking world. Meanwhile, Mannish Boy is found near a well and pretends to be sick. He is given to the care of the Joestar Group by a woman claiming that they need to bring him to a hospital. They reluctantly agree, without knowing the woman was actually scared of him and that the baby was a Stand user.
Onboard an airplane, Mannish Boy uses his Stand to attack Noriaki Kakyoin and Jean Pierre Polnareff. Kakyoin remembers everything and tries to warn Polnareff but Death Thirteen attacks. It almost kills Polnareff but the Frenchman is woken up by Joseph Joestar, who tells him to change the baby's diapers. Kakyoin is left alone with Death Thirteen, revealing that he is the baby. Kakyoin tries to cut his arm with a knife but Mannish Boy dismisses the move as futile. In addition, Kakyoin struggles hard and his violent movements in his sleep in response to the attack end up downing the plane. As no one remembers what happened once awaken, everyone believes that Kakyoin is becoming unstable. Kakyoin then discovers the words "Baby Stand" carved on his arms and begins to suspect the baby. He accuses the baby of being an enemy but no one believes in.
A scorpion crawls into Mannish Boy's crib, forcing him to kill him. However, he's seen by Kakyoin who runs to the crib and tries to find the scorpion. However, the baby hides the scorpion in his mouth which preserves his cover although he's almost unmasked when Joseph tries to feed him. Desperate, Kakyoin shows the carving on his arms, which only convinces the others that he's mad. As a last resort, Kakyoin decides to summon Hierophant Green and attack the baby but Polnareff knocks him out. Put back in his crib, Mannish Boy is able to spit out the scorpion and wait until everyone is asleep.
Jotaro, Joseph and Polnareff find themselves in Death Thirteen's nightmare world where he spends a few instants humiliating the heroes. However, he's then attacked by Kakyoin and his Hierophant, because falling asleep with one's Stand out allows one to utlize them in the nightmare. Hierophant Green strangles Death Thirteen but Mannish Boy sees that Kakyoin's going easy on him because he's a baby. By controlling his nightmare, he attempts to scythe Hierophant from behind but it has already infiltrated the inside of Death Thirteen. Mannish Boy is forced to heal Kakyoin's wounds and leave the others be.
In the morning, Kakyoin teaches Mannish Boy a lesson by mixing some of the baby's excrement into his baby food. Naturally, Joseph and Polnareff, who are clueless about this and believe Mannish Boy to be hungry, decide to feed him the contaminated food.
It can be inferred that Mannish Boy was given to the care of someone else after the group is rescued and he doesn't dare to attack the group again.
Chapters / Episodes
The events from Death Thirteen occur in a different way. Unlike the printed storyline, in the game Mannish Boy attacks the group from inside a plane en route to India.
Mannish Boy appears only in Story Mode cutscenes; placed before and after Kakyoin's fight with Death Thirteen.
Death Thirteen's Nightmare Dream world where the Joestar Group was trapped, is a playable stage in the game. There is a stage gimmick where Death Thirteen will hunt your character.
JoJo's Pitter-Patter Pop! (Android/iOS)
- Although Mannish Boy only appears in the PS1 version of Heritage for the Future, his Stand, Death Thirteen, appears in all versions as an NPC that can only be fought by the protagonists when certain conditions are met.
- Mannish Boy's catchphrase of "lali-ho" is a reference to sleep spell in Dragon Quest, which in turn references a same catchphrase used by Dwarves in the Final Fantasy franchise.
- Mannish Boy was not given a proper name until years later, eventually being officially documented in JOJO A-GO!GO!.