Denji, the main protagonist of Chainsaw Man (and the person who literally becomes Chainsaw Man), is one heck of a character. He's unlike just about any other Shonen protagonist in existence and has actually achieved quite a lot in the chaotic world of Devils and horrors that he lives in. From killing Devils to managing to flirt with his boss, Denji's done it all.
So, let's go through all of Denji's biggest achievements throughout the Chainsaw Man manga while waiting for the highly anticipated anime and rank the top ones from least to most impressive.
Disclaimer: HUGE spoilers for the Chainsaw Man manga are below.
10 Completing His Training With Captain Kishibe
This first event takes place in the middle of the Katana Man arc, and it's right after Aki ends up in the hospital after fighting against Katana Man and losing his long-time work-friend Himeno. After these events, Makima takes both Denji and Power to Captain Kishibe, the Captain of Special Division 1 and the strongest "pure human" character in the series.
Kishibe then trains both Denji and Power to become better Devil Hunters and fighters, and this training process involves killing both of them a ton until they are able to beat Kishibe in a fight or at least impress him. Frankly, it's some real "spartan-style" training that involves a ton of pain, death, and critical thinking, the last of which Denji is especially bad at.
9 Outsmarting Katana Man
After training with Captain Kisibe, Power and Denji both find themselves part of the mission to retaliate against the people who tried to kidnap Denji in the first place (and killed Himeno, the girl who puked in Denji's mouth), which includes both Sawatari who has a contract with the Snake Devil, and Katana Man. A lot of things happen in this chaotic arc involving Zombies, the Ghost Devil, the Snake Devil, and more. Eventually, Chainsaw Man ends up fighting head to head with Katana Man again. But this time, he actually uses his head (well, legs) and ends up beating the guy by outsmarting him.
And after putting Katana Man back together and waiting for him to wake back up after regenerating, Denji then manages to cheer up Aki with one of his dumbest decisions by competing against him to see who could kick Katana Man hard enough in the groin to have Himeno hear it up in heaven, which is just so perfect.
8 Making It As Long As He Did As A Human
Denji says it himself multiple times throughout the story, as long as he can eat every day and has a nice bed to sleep in, he's living a cushy life. Remember, Denji's deadbeat dad died and left his absurd amount of debt to Denji to take care of.
And, for most of his life, the kid did odd jobs and eventually hunted Devils to make just enough money to keep the Mafia off of his back, with almost nothing left for himself to use for food and shelter. He dreamed of putting jam on the bread he ate every day but could never afford it. So, the fact he even survived long enough (especially since he likely had the same heart condition his mom had) to become Chainsaw Man is impressive.
7 Eating The Most Twisted Meal Of All Time
In the final arc of Chainsaw Man, well, the final of "Part 1", so much chaotic stuff happens. Makima reveals her true self as the Control Devil to Denji, kills him, brings out the Chainsaw Devil, and a whole war goes down. But, after Power brings Denji "back to life" with help from Poochita, the kid actually manages to take Makima down in a clever scheme.
Then, after temporarily "killing" her, Denji figures out a way to get around her regenerating, and that's by...well, eating her. It's disgusting in more ways than one, but the guy literally spends months slowly making different meals out of a fridge full of Makima's flesh and consuming them, so she can't come back, and somehow, it actually works.
6 Beating Up Santa Claus
In this setting, Santa Claus is someone who made a contract with the Doll Devil or is perhaps the Doll Devil itself and is able to turn people into its puppets with a touch (and those puppets create more puppets). And, after "trading" Denji to the Darkness Devil in Hell, Santa Claus gets a piece of the Darkness Devil's flesh and becomes way more powerful.
So, the sheer fact that Denji comes back, fights Santa Claus, and manages to beat her is incredible. And he does this by lighting himself on fire to use what he calls "the power of light" to slow her regeneration before tearing a hole through her with a chainsaw dive-kick.
5 Outlasting The Eternity Devil
The whole Eternity Devil arc of Chainsaw Man is such a wild ride. It has a lot of fantastic character interactions, an interesting mystery, and some shocking twists. And one twist is how they actually manage to defeat the Devil. The Eternity Devil actually "traps" Denji's group in a wait, basically forcing them to either sacrifice him to it or starve to death.
But, Denji notices it's afraid of his chainsaws, so he decides to hop right into its open "mouth" and start cutting it up. This battle between Chainsaw Man and the Eternity Devil then goes on for three days, with Denji dying numerous times but then drinking the blood from the Devil's wounds to regenerate. Finally, the Eternity Devil is so tired of the pain and torture of being cut with Chainsaws that it actually gives up.
4 Beating Aki In The Worlds Most Tragic Duel
The battle between Aki and Denji during the Gun Devil Arc is so painfully heartwrenching. The guy devoted his entire life and all that he was to defeating the Gun Devil, and yet, in the end, he becomes a Gun Fiend. Not to mention that in his warped and possessed brain, Aki thought he was having a simple snowball fight with Denji when in actuality, he was using his new Gun-like limbs to destroy buildings, kill innocent civilians, and tear Denji apart.
That said, he was still a Fiend of one of the strongest Devils in existence, and Denji managed to beat him, which is pretty huge.
3 Managing To Trick & Defeat Makima
This was touched on a bit earlier, but it's still hard to believe that Denji managed to come up with a way to beat Makima, the literal Control Devil, as well as think of a way to circumvent her seemingly infinite regeneration.
Not only does Denji use his Poochita-heart clone as bait to make Makima think she had finally won, but he also uses Power's blood on his Chainsaw to stop Makima's wounds from healing. It's a truly calculative move from a guy who never went to school.
2 Teaching Power To Behave Herself (Sort Of)
Some may think that this next feat is too highly ranked, but they're wrong. When Power is first introduced into the story, she's uncontrollable. She does what she wants, is willing to kill humans easily, and is a typhoon of pure chaotic energy.
But, after moving in with Denji and Aki, Power starts to slowly change. Granted, she never becomes anything even remotely resembling a "well-behaved person," as she's still a picky eater and even ran Denji over (and an assassin in disguise) with a stolen car, but she does get a lot better. By the end of the story, she's basically become Denji's surrogate bratty little sister.
1 Somehow Making It Back From Hell
And finally, let's talk about Denji's biggest feat, making it back from Hell itself. Now, in the world of Chainsaw Man, Devils can "die," but they're not really dead. Instead, they go to Hell to be killed there and return to Earth. But, when Santa Claus sends Denji and his group of powerful Devil Hunters to Hell, they aren't Devils, so they'll die for real here. Yet somehow, even after coming face to face with the Darkness Devil, Denji manages to return to the world of the living.