In Tatsuki Fujimoto's Chainsaw Man, Devils are terrifying monsters created from the deepest fears held by humanity. Devils are also immortal, allowing them to be reborn in Hell every time their physical bodies are destroyed. While they can't be permanently killed, Devils can be severely hurt and weakened. Those Devils who become weakened in battle or due to a lack of feeding on human blood will often cling to their physical manifestation by alternative means, including by taking over the body of a human being to become a Fiend.
Fiends are considerably weaker than their full-blown Devil forms, constrained by the limits of the human body they inhabit. Still, that's often preferable to being reborn in Hell, where they must constantly fight with considerably more powerful devils for all eternity. Even if they are no longer at full power, many of the Fiends in Chainsaw Man are still incredibly powerful. The power of a Fiend is directly related to the power of the Devil that inhabits its body, meaning that some Fiends can even be stronger than other full-fledged Devils born from lesser fears of humanity.
10 Pingtsi is the Fiend of an Obscure Devil Who Knows Many Obscure Facts
Original Devi: Futakuchi-onna
Pingsti's true identity as a Devil is unknown, and she doesn't get much screen time in CSM. What is known about Pingtsi is that she is one of Quanxi's late-lovers, and is particularly obsessive over Quanxi to the point that she constantly spits random facts just to try to impress her girlfriend. This is a quality she shares with Asa, who also spent the majority of her first date with Denji at the aquarium listing off facts about sea creatures. This could indicate that, just like Asa, Pingtsi is actually quite awkward in regular social interactions, despite how talkative she is.
Unlike Asa, who likely had to research all the facts she spewed to Denji on her own, Pingtsi's Devil ability does much of the work for her. Pingtsi's ponytail takes on the shape of a spiritual entity, which can turn into a magnifying glass and provide her with useful information on the things she looks at through it. Pingtsi's magnifying glass can provide her with information such as what Devils a person is contracted with, and even help her to speak a language she has no prior knowledge of. Notably, Pingtsi's ponytail resembles the popular image of the Japanese folktale of the Futakuchi-onna: a monstrous demon who curses women.
9 Princi Embodies One of Humanity's Most Popular Phobias
Original Devil: Spider
Princi is a member of Public Safety's Experimental 4th division in Tokyo, making her a coworker of Galgali, Beam and Angel. As the Fiend of the Spider Devil, Princi is understandably powerful, as her strength is based on humanity's fear of spiders -- one of the most widely held phobias in the world.
Perhaps due to her acute awareness of how people fear spiders, Princi ordinarily takes on a human appearance, only changing to her more fiendish spider form when in combat. In battle, Princi's spider legs are so sharp that she can stab through her enemies. She can also burrow underground like some spiders and scorpions do in real life, which allows her to hide from predators (like the Darkness Devil) and sneak-attack her opponents.
8 Nail Will Hammer Home Their Beliefs Into Their Enemies' Skulls if Necessary
Original Devil: Nail
The Nail Fiend was first introduced during the Chainsaw Man Church arc. Nail was a major factor in the infiltration of the Church alongside Katana Man. While they haven't shown many powerful abilities like other Devils and Fiends, Nail does have phenomenal combat skills and supernatural agility that allows them to fight multiple gun-wielding enemies simultaneously.
Nail has an androgynous style, looking physically like a male, but wearing their suit like most female Public Safety officers do. They're also quite unpredictable, often saying one thing but then acting in the exact opposite manner. These aspects of Nail’s personality make them one of the more interesting new characters to watch in Part 2 of CSM, as their Fiendish behavior often calls back to Power's own unbearable-yet-endearing qualities.
7 Long's Mytholigical Origins Could Make Her Stronger Than She Looks
Original Devil: Unknown, but Possibly the Dragon Fiend
Long is one of Quanxi's beloved girlfriends. Not much has been shown of her in the series, but some of her power has been seen. Namely, Long has the ability to blow fire, which has contributed to fans' belief that she may be the Fiend of the Dragon Devil. This is unconfirmed, but it does match up with her almost reptilian eyes and the horns on her head -- both known characteristics of dragons.
Aside from her appearance, another hint at Long's identity as the Dragon Devil Fiend is her name. In Chinese mythology, dragons are also referred to as "Lóng". This is particularly relevant considering both Long and Quanxi originate from China. While she isn't shown using much of her abilities, if Long truly does embody the fear of dragons like she appears to, she could potentially be far more powerful than she looks.
6 Beam is the Best Sidekick Chainsaw Man Could Ask For
Original Devil: Shark
Few characters in Chainsaw Man, let alone among the Fiends, are as beloved by fans as Beam. Beam is obsessively enamored with Chainsaw Man, and will follow Denji no matter what ridiculous idea he proposes, even if that means mounting Beam like a horse and riding him through the streets against the Typhoon Devil.
As the Shark Devil Fiend, Beam has the ability to pass through any physical surface as though he were swimming through it. He also has extremely sharp teeth, and can even manifest his Shark Devil form to bite through enemies and swim more quickly than usual. As a shark, Beam also has an incredible sense of smell, allowing him to tell that Reze was a Devil Hybrid just by her scent alone. This long list of abilities makes Beam the perfect sidekick to serve his beloved "Lord Chainsaw".
5 Galgali is a Fiend so Powerful He Has to be Restrained
Original Devil: Violence
As the Violence Fiend, Galgali is understandably strong in battle. He mostly fights through kicking and punching, but his strikes are strong enough to blow straight through flesh. Galgali is so strong that he has to wear a poisonous mask at all times to restrict his true strength, which would make him difficult for even Public Safety to handle.
The one time Galgali's mask was removed was by Kobeni in the fight against the Darkness Devil in Hell, as a last-ditch attempt to help her survive. While everyone else was easily dispatched and dismembered by the Darkness Devil, Galgali was the only one able to fight back, even growing an additional arm from his mouth after both his arms were cut off. This refusal to stop attacking, even when anyone else would be helpless in that situation, truly embodies Galgali's nature as violence itself. Unfortunately, there was still little that he — or anyone else, for that matter — could do against the overwhelming power of Darkness.
4 Aki Became the Thing he Hated Most
Original Devil: Gun
Aki's time as a Fiend was short-lived, but that was really for the best for both him and fans alike. It was a truly tragic irony that led him to become the very thing he always sought to destroy, after the Gun Devil took control of his body in order to survive Makima's attack. No Chainsaw Man fan will ever forget the moment Aki knocked on Denji's door, and the horror Denji found when he answered.
Aside from the strong emotions he made fans feel, Aki's strength as the Gun Fiend deserves to be acknowledged. While Denji was holding back considerably during their fight because he didn't want to kill his friend, he was ultimately left with no choice after the senseless destruction Aki unknowingly caused. The Gun Devil was easily one of the most powerful Devils in the entire series, so it makes sense that Aki would be one of the most powerful Fiends when possessed by the Gun Devil.
3 Cosmo Has Immense Power With Minimal Combat Ability
Original Devil: Cosmos
Few Devils in Chainsaw Man have a power as devastating as the Cosmos Fiend, let alone Fiends themselves. Cosmo represents the vast expanse of space, and the fear of the unknown that comes along with it. Like the cosmos of real life, the Cosmos Fiend contains the knowledge of all things in the universe, and represents humanity's utter lack of the ability to comprehend it all. That's why, when Cosmo uses her ability on Santa Claus, it renders Santa completely incapable of thinking of anything other than "Halloween" for the rest of her life.
Cosmo doesn't seem to have any physical fighting prowess other than the general strength and durability that any Fiend would tend to have. Instead, the extent of her power lies in the fact that, once she can bring an enemy into her world, she can render anyone completely helpless in the face of the unimaginably vast knowledge of all things that exist in the cosmos.
2 Power Was Originally One of the Strongest Devils
Original Devil: Blood
As the Fiend of the Blood Devil, Power is easily one of the all-around-strongest Fiends shown in the series so far. That's especially the case considering that she gains the ability to access her full Devil powers during the fight with Makima, allowing her to take on her full Blood Devil form, which gives her the strength to at least stand up against the Devil Hybrids.
Power's main Devil ability lets her control her own blood, allowing her to shape it into any form and even control its density to create strong physical objects. Power also has the power to control the blood of others when touching them, though she has less control of others' blood than her own. This lets her take on a medical role in combat, which is something most Devils can't do. Given how selfish Power tends to be, though, she'd ordinarily never use her power to save a human unless pressured to.
1 Asa's Status as a Fiend — or a Hybrid — is Uncertain
Original Devil: War
While Asa's status as a Fiend or a Hybrid is heavily debated (and for good reason), if she is a Fiend, she's undeniably the strongest. As the vessel of the War Devil, Asa is able to transform anything she feels she owns into a weapon. At first, she has to touch the object to make it a weapon, but after her power increases, she can even create weapons from objects at a distance.
The reason Asa's status as a Fiend is called into question is due to the nature of her transformation. Unlike other Fiends, Asa is able to retain control of her body when Yoru allows her to. This implies that she’s more like a Hybrid than a Fiend, but there are also aspects of her situation that suggest she may be a Fiend. For example, the very fact that Yoru took over her body as opposed to becoming an organ inside her like in Katana Man's and Chainsaw Man's cases makes her more like a Fiend than any Hybrid in the series.
