Manako is short and round, with light pink skin and one large green eye. She also has two small horns, sharp teeth and wears a thick black belt that usually covers her mouth.
Manako has a cowardly personality, as she hides away in a restroom in the Monster Association Headquarters, planning to wait out the heroes' attack in there, and refuses to come out when another monster reports that the heroes have already started their assault. She is shown to be clearly afraid of S-Class heroes, as seen when she has an extreme reaction to seeing Flashy Flash when he breaks through the wall into the restroom she is hiding in with Saitama. She is often seen covered in sweat with every appearance, showing she is on edge and is easily scared.
When Saitama and Flashy Flash take her as a hostage to lead them to the Monster King, Manako schemes to kill them both behind their backs. Planning to take them off the tracks and into a ravine when traveling in a minecart and planning to smack Saitama on the back of the head with a rock when trapped in the rubble of the Monster Association base, fearing that if she is no longer of use to the heroes, she will be killed.
Manako is using the restroom when Saitama and Flashy Flash came and took her hostage, using the monster to lead them to the Monster King's lair. As Manako was leading them through the tunnels, her plan was to de-rail them at a switching point to kill the heroes and herself, but chickens out when she gets closer to the broken rail and sees the vast fall.
Soon after, the trio passed through an excavation site in the Monster Association base. Other large mining monsters attacked them but were quickly killed by Saitama and Flashy Flash. Manako almost fell to her death but was saved by Saitama, who sacrifices the gold he was stealing from the Monster Association by doing so. A frustrated Saitama then pulls at Manako's cheeks to wake her back up after she fell unconscious from fear of falling to her death.
Later, she, Saitama, and Flashy Flash encounter the merged form of Psykos and Orochi, much to Manako's terror. When the merged monster tries to absorb Saitama, it slips off his shiny bald head. It is then punched, causing Psykos' portion to momentarily disappear while Flashy Flash and Manako watch on with blank stares. When Tatsumaki pulls the Monster Association Headquarters out of the ground, Manako, Flashy Flash, and Saitama are nearly buried but Saitama saves them. In spite of this, the trio is left in complete darkness afterward. However Manako thinks that once she has outlived her usefulness Saitama will kill her. In a bid to knock him out she lifts a large rock from the wall and it reveals Flashy Flash has been behind that rock the whole time, trapped under the rubble. She is so startled by this her eye lights up which gives the heroes full visibility of the area. Saitama under the orders of the immobilized Flashy Flash asks for a light.
During the battle between Psykos, Orochi, Tastumaki, and Genos, Saitama and Manako continue working to free Flashy Flash from the collapsed tunnel. As the battle rages above them, Saitama remarks how hungry he was, to which Manako concurs with similar feelings. She then tightens her belt to an immense degree to the confusion of the two heroes. The monster explains that doing so helps reduce the feeling of hunger, and though initially doubtful, Saitama tries this technique as well, which actually works somewhat. The bald hero wonders to himself if he had achieved enlightenment with this revelation while Manako observes that the three of them are the type of people who are dependent on others; a sentiment that Flashy Flash asks to not be included in. As the unlikely pair discuss what Saitama will cook when he gets home, Flash finds solace in how no one else will see him in such a pitiful state.
Eventually, Saitama and Manako manage to free Flashy Flash, save for his arm. Saitama pulls out one last object; a mysterious black cube, and nonchalantly tosses it to the side. The cube's weight imbeds it into the ground and Manako tries to lift it, but to no avail. Suddenly, the cave-in begins to tremor violently as Tatsumaki lifts the entirety of the Monster Association Headquarters out of the ground. However, Flashy Flash's katana, Instakill, was stuck to the section of the hideout that Tatsumaki ripped out of the ground, resulting in the sword breaking at the hilt and its blade still embedded in the rock. The two heroes end up in a quarrel about how much time they wasted over the ninja's precious sword, but Manako takes this as an opportunity to finally escape. She begins to climb into the hole where Flashy Flash was once trapped, but stops halfway through in surprise. Saitama and Flashy flash peer into the hole with her, and the scene pans out to a monolithic humanoid figure, motionless in a fetal position inside a starlit void.
As it turns out, Saitama, Flashy Flash, and Manako cannot see anything in the pitch black hole. Flash harshly orders Manako to use her ability, much to her annoyance, but the monster is still unable to detect anything. Suddenly, a mysterious voice speaks to the trio through their minds, ordering them to place their hands on the black cube and make a fervent wish. It says that if it deems them worthy, it will bestow its power upon them, or they will be confiscated. Before they could properly respond, Blast appears from a black hole-esque portal, relieved that he made it in time. He explains the properties of the cube before sending it through a smaller portal. After Flashy Flash attempts to kick Blast as a way of testing him, the top ranked hero notices Manako, and menacingly asks why she is there. Manako gives a desperate side-glance to Saitama, who casually explains that she is their "tour guide" and flashlight. Apparently satisfied with this explanation, Blast prepares to warp the trio out of the cave-in, asking that they send Sitch and Tatsumaki his regards.
Manako, Flashy Flash and Saitama are then teleported to the surface by Blast. As Saitama and Flashy Flash leave to do their own business, she is left alone. Later, after Flashy Flash is defeated by Platinum Sperm and sent to her whereabouts, she is shocked to see the unconscious S-Class hero. While she tries to wake him up, Sweet Mask arrives and attempts to kill her, having misunderstood her intentions as assassination. Fortunately, a massive ship and a flood of water run past her and Sweet Mask, saving her from the latter. However; Manako is dragged off by the sea while gripping onto Flashy Flash tightly. Soon, Pig God arrives and saves her along with many others from the sea by swallowing them whole for safety.
Afterwards, Pig God spits Manako and everyone else out once he reaches for safety, where she then stays with Flashy Flash for protection. Manako and everyone else present soon witness multiple immense explosions caused by the battle between Saitama and Garou. Soon, Sweet Mask notices her and in a hostile way, questions Flashy Flash why he is with her, a monster. Flashy Flash replies that Manako is an "exotic animal" he found that was useful for lighting up the darkness, with a scared Manako confirming and greeting Sweet Mask. At this moment, Garou appears before Manako and many other heroes present, frightening them.
Manako does not know who Saitama is, and at first doesn't see him as a big threat as he is just a low ranked hero. She eventually comes to fear him after witnessing his amazing power up close as he kills powerful monsters in one punch. She has often plotted to try kill Saitama in the mine carts, or even escape him while she gets the chance but decides not to. Manako is also seen hiding behind him for protection when she feels in danger.
Manako is scared of Flashy Flash, understanding him as an S-Class Hero and his power. She was hiding in the bathroom away from him before getting kidnapped. Throughout her adventures with him, she is still very scared of the hero and is worried she will be killed after her use is over. She has sometimes plotted to try kill him or escape when she can get the chance, but decides not to at the last minute.
After Flashy Flash is defeated in his fight against Platinum Sperm and Garou, Manako shows concerns about his injuries and attempts to wake up the ninja, who is lying unconsciousness on the ground.
Despite being taken away by Saitama and Flashy Flash, she is shown to still be loyal to the Monster Association.
Abilities and Powers
Although her disaster level is unknown, Manako seems to be a relatively weak monster, hiding in a toilet in the Monster Association Headquarters to avoid battles. She is also unwilling to fight against S-Class heroes and is visible frightened upon seeing Flashy Flash.
Enhanced Strength: Manako can lift fairly large rocks with ease. She also had a tight grip as she managed to keep hold of Flashy Flash despite the flood of water making it difficult to do so.
Night Vision: Manako can see in the dark. When she and Saitama were trapped by rubble underground of Z-City, Manako attempted to sneak attack Saitama who couldn't see his surroundings due to the darkness.
Multiple-Purpose Eye-Light: Manako's eye can project different forms of light with different functions depending on how she presses her two horns.
- Regular light: Manako does not press any horns. This ability can also activate accidentally when she is startled or surprised. This light is bright enough to blind both Saitama and Flashy Flash.
- Searchlight: Manako presses both horns at the same time to extend the range of her eye-light.
- Thermostat: Manako presses the right horn to emit a light from her eye that can detect temperature.
- X-ray: Manako presses the left horn to emit x-rays from her eye.
- Manako (眼) means eyeball.
- One-Punch Man Manga; Chapter 122 (Online), page 12
- One-Punch Man Manga; Chapter 122 (Online), page 13-14
- One-Punch Man Manga; Chapter 125 (Online), page 12
- One-Punch Man Manga; Chapter 131 (Online), page 18
- One-Punch Man Manga; Chapter 122 (Online), page 12-14
- One-Punch Man Manga; Chapter 125 (Online), page 9-13
- One-Punch Man Manga; Chapter 126 (Online), page 2-15
- One-Punch Man Manga; Chapter 131 (Online), page 19
- One-Punch Man Manga; Chapter 131 (Online), page 19-21
- One-Punch Man Manga; Chapter 139 (Online), page 2