Quanxi/History

History
Quanxi worked as a Devil Hunter and became known as a 'First Devil Hunter'. While working as a Devil Hunter, Quanxi met Kishibe while he was young. During their first meeting, Kishibe asked her to go out with him. She rejected him immediately by punching him. This occurrence has been repeated several times until nine years later after their first encounter, she declared that she was interested in girls, Kishibe then stating that he had expected it.

After that, at some point in time, she left being a Devil Hunter and went to China. She formed a harem of fiends during her stay in there while working for that country.

International Assassins arc
In China, Quanxi was in bed with four fiends, when a member of the Chinese military gave her a job to go to Japan and capture the Chainsaw Devil. He said that the general will authorize any reward for her work due to the danger of the mission.

Quanxi then asked her fiends what they wanted, and they respond with donuts, blood and Halloween. Quanxi tells the man that she wants her girls to receive human rights and basic education and the man tells her that they'll look into it, provided she succeeds.

In Japan, Makima discusses with Kishibe about the various threats that are coming from overseas including a rumor that Quanxi is on her way. Kishibe says that he isn't keen to fight her and that she'll be tricky but there is no use in taking precautions against her. Quanxi arrives in Japan and visits a sushi restaurant with her fiends. She announces that she's out of energy for the day so she'll resume the mission to capture Denji tomorrow. She ends up having sex with her fiends all night long making them exhausted the next day and after they learn that Santa Claus is also in the area they decide to put off getting involved until tomorrow again.

Quanxi and her fiends arrive through a back alley near the department store where Denji and his bodyguards are under assault by Santa Claus. She approaches a group of devil hunters who were trying to reinforce Denji's group. Quanxi comments in Chinese to let her fiends know that they should clean up the mess that will be left behind. She unsheathes her sword and after crouching low launches into a sprint that takes her through the devil hunters and army of dolls, decapitating or dismembering all of them at high speed. Aki sees Quanxi's attack through his future sight and shouts a warning to Angel Devil and Nakamura. He manages to get his blade in between Quanxi and the Angel Devil, saving the Angel Devil's life but Nakamura is decapitated and both Aki and the Angel Devil are knocked unconscious.

As her blade shatters Quanxi leaps into the midst of the group and kicks Denji into the air, incapacitating him. She swiftly dodges strikes from Tamaoki and Kusakabe and kicks them both in the jaw, knocking them out. Hirofumi Yoshida summons the Octopus Devil and blocks one of Quanxi's kicks. The Octopus Devil creates a smokescreen of ink in the air letting Hirofumi get closer to Quanxi but she quickly defeats him.

Before she can stab him she is interrupted by Kishibe who arrives while holding two of her fiends hostage. Quanxi sits down at a nearby table and Kishibe passes on his hostages to Denji and Power. The two of them have a conversation while Kishibe subtly communicates another message to her by writing on a piece of paper. He informs her that Makima is listening in to the conversation and that he plans to kill Makima; if Quanxi assists him then he'll tell her everything and guarantee her safety.

Instead of accepting his offer, Quanxi relates a story to him about a news reporter she had a crush on and later changed her mind about. As she finishes telling her story, with the advice that ignorance is bliss and that Kishibe should simply be a good dog for Public Safety and keep his collar on, Aldo appears and tries to shoot Denji. Kishibe kicks Denji out of the way of the gunfire and Quanxi uses it as an opportunity to punch Kishibe in the face.

Quanxi follows up with a knee to his head and stops his counterattack by catching his knife between her fingers. Kishibe attempts to kick her but she catches his leg and throws him out the window. Aldo shoots at Quanxi's fiend who is holding Denji down but before he can press the attack he is grabbed by Quanxi and thrown out of the window to land on Kobeni Higashiyama's car.

Quanxi politely asks Power to let her hostage go, claiming to not want to fight her. Beam appears out of the ground and knocks the fiend off of Denji, allowing them both to run away. Before Quanxi can follow them, Hirofumi stands back up and demands a rematch. They exchange blows with Quanxi initially having the upper hand but Hirofumi managed to land a powerful kick on her face, damaging her.

After fighting some more Quanxi picks up Hirofumi and throws him out of a window, though he saves himself from falling to the ground by using the Octopus Devil. She looks back at Aki, the Angel Devil, Tamaoki, and Kusakabe who have all picked themselves up, and asks if they want to fight next. Suddenly everything goes dark an enormous hand reaches down from the sky, transporting everyone inside the mall to Hell.

In Hell, Quanxi observes that Denji isn't able to fully transform after Aki pulls his chainsaw cord and deduces that it must be because of a lack of sufficient blood. She calls a temporary truce after observing that something is wrong with the fiends. Quanxi asks her fiends Long and Pingtsi if there is any way to escape but they're panicking too much. Pingtsi warns her that they're being watched by a powerful devil; one of the devils that embody primal fears and have never died. Pingtsi requests permission to commit suicide but Quanxi reassures her that she'll get them out of there.

Pingtsi cries out that it is already too late and that the Darkness Devil is upon them. A door opens in the sky and a dark mass descends. Quanxi prepares to fight alongside the other devil hunters but they are all completely blitzed by the speed of the Darkness Devil which moves through them and removes all of their arms. Quanxi tries to attack the Darkness Devil alongside Tamaoki after the Darkness Devil begins slaughtering them, but before she can land her kick the Darkness Devil scythes out with its arms, cutting Quanxi, Tamaoki, Long, and Pingtsi into pieces and scattering their body parts in the area.

After her body parts were returned to Earth alongside everyone else, Tsugihagi recovered her head and activated the trigger to her transformation before dropping Quanxi's head into a pile of enemy dolls. Quanxi fully regenerated and transformed into her hybrid state; slaughtering the dolls with rapid-fire projectiles. She proposed a temporary alliance to Denji so that she could get revenge against Santa Claus for the deaths of Long of Pingtsi. With that, she disappears in a burst of high speed and attacks Santa Claus directly with a hail of arrows which shatter her body but do no lasting damage due to her regeneration in darkness. Santa Claus greets her as the world's first devil hunter and wonders how she will hunt an invisible hunter.

Quanxi saves Denji from being swarmed by a group of dolls and tells him to treat them as if they're only impersonating humans instead of reclaiming their former memories. She claims ignorance is bliss so that even if her advice is not true, he will still be able to kill them. Santa Claus bursts out of the wall next to her and grabs her, announcing with satisfaction that she finally caught her, Quanxi easily repels her with a barrage of arrows.

She notices that night is coming which is a bad sign, as Santa Claus grows even more powerful and takes on a darker form. Quanxi tries hitting her again with a barrow of arrows but this time Santa Claus catches them out of the air. She announces that she took the time to create a couple of extra dolls, revealing Long and Pingtsi who have taken another of Quanxi's fiends as a hostage. Quanxi is stabbed through the chest by Pingtsi and Santa Claus wonders if she'll be able to turn Quanxi into a doll, although she is interrupted by Denji before she can carry it out.

After Denji defeats Santa Claus and is gloating over her ruined body, Quanxi - back in her human form - steps up behind Denji and swiftly decapitates him before he can react since the truce between them has expired. Santa Claus promises that she'll add Quanxi to her collection of dolls one day, but Quanxi instructs her subordinate Cosmo to give Santa Claus an all-out taste of Halloween which drives her insane.

Kishibe and Hirofumi both approach her and though Quanxi is ready to fight them, she stops when she notices them putting on blindfolds and an armed Makima arriving with them.

Quanxi drops her sword and surrenders to Makima, begging that the lives of her women be spared but Makima cruelly repeats the words her subordinates stated earlier and both Quanxi and her two surviving fiends are decapitated instantly, splatting her blood onto Kishibe's cheek.

Control Devil arc
Despite her unceremonious "death", Quanxi was revived and brainwashed offscreen by Makima for her own needs. She is summoned as part of Makima's newly-formed Special Division 5, a team of weapon hybrids created for the sole purpose of battling the fully-powered Chainsaw Devil. While under Makima's control, Quanxi behaves protectively and with great affection towards her.

Once Makima commands Special Division 5 to attack, each member activates their weapon trigger, transforming into their Hybrid forms. They all leap from their respective spots to lunge straight toward Chainsaw Man. Before any of the Hybrids can land a single blow on him, they are blown back by Chainsaw Man leaping forward as he slices through Quanxi and Miri Sugo with one of his chainsaw legs. The three crash through several skyscrapers before landing in an apartment complex. As he gets up, Chainsaw Man kneels over Quanxi and Miri's tattered bodies, clutching each of their severed heads before fighting the other Hybrids.

At some point in the future, Special Division 5's Hybrids are revived once more by Makima, who brings them all to a graveyard to confront Denji. Once Makima finishes monologuing her thoughts of erasing anything she dislikes to Pochita (who is disguised as Denji), Quanxi and the other Weapon Humans transform into their Hybrid forms for the final battle.

After Pochita defeats most of the Hybrids, Quanxi appears from behind and launches multiple arrows to pierce through his body. She then stands beside Makima, guarding her, while Barem attempts to burn Pochita alive after he is piled up by a group of zombies from the Zombie Devil.

Unfortunately, Pochita uses his chain whips to launch himself straight towards Makima's group. Using his chainsaws, Pochita slices Barem in half while Quanxi blocks Pochita's attack using her crossbows. She proceeds to launch more arrows at Pochita but ends up decapitated in the process. Quanxi's headless body then collapses to the ground, defeated.

Current arc
Several months after being freed from Makima's control, Quanxi rejoins Public Safety. She is sent to stop the Weapons from causing a massacre in East Ogikubo. Upon arriving, Quanxi swiftly dismembers the Weapons located there before they can harm anyone around the plaza.

Once that is done, Quanxi reports back to her superiors that the mission was successful, and that Special Division 7 should be sent inside the Chainsaw Man Church 20 minutes after the first bit of media coverage.

Quanxi later rescues Denji, Nayuta, and Fumiko Mifune from Barem and his army of faux Chainsaw Devils on top of a building. She then jumps off the building to take the group to safety. While in midair, Quanxi bites Fumiko's exposed midriff to extract some of her blood. Upon landing, Quanxi's legs instantly break but they immediately regenerate after she consumes Fumiko's blood. Setting the group down, Quanxi continues cutting down hordes of faux Chainsaw Devils alongside nearby Devil Hunters around the area.