More often than not, Shonen takes an unsuspecting male protagonist on a journey that will change his life. Whether it be for good or bad, the protagonist often comes out with some extra baggage. Take, for example, Edward Elric. At the prime age of 15, he lost his arm and brother due to an alchemical mishap. Since then, his life changed as he went on a journey in pursuit to turn things back to normal. Tatsuki Fujimoto took this general idea and somehow made it worse.
This is the story of what happened to Denji in Chainsaw Man. Spoilers ahead!
What Happened to Denji? Answered from Beginning to End.
Denji’s Childhood
Despite Denji being the titular protagonist, we know very little of him. The way his story is told is similar to Michael Keaton’s Batman. Only bits and pieces of his past are provided to the reader. The series focuses more on the present which turns Denji into an unreliable narrator.
As a child, he didn’t have a good life. He lived with his father and constantly dealt with poverty. To try and live a normal life, Denji’s father likely loaned a lot of money. Unfortunately, with nothing to pay back, they plunged into debt. His father turned to alcohol to likely escape reality and eventually erupted. In return, Denji killed his father in self-defense.

The ramifications of his act barely registered in his mind. In his desperation to escape reality, he told a lie to himself. His father had chosen to hang himself. His mind warped the memory and suppressed the trauma. It is from here that Denji began to lose hope.
How it All Began
Left without knowing what to do, he came across Pochita. He told the little Devil to kill him but found the latter incapable. It had been injured and dying from its wounds. Upon seeing its situation, the trauma within Denji’s mind came up. Perhaps in a way to absolve himself of his sins, he entered a contract with the Devil. Then, the rest is history.
Denji worked as a Devil Hunter for his father’s loan sharks to pay off the debt. Eventually, the loan sharks no longer found a use for him. They had him killed and Pochita turned itself into his heart to keep him alive.

Pochita’s sacrifice had Denji reborn in a rage. After killing the loan sharks, he met Makima who decided to take him in. Her blatant affection and kindness for Denji blindsided the love-starved boy. This made him fall in love with her quickly despite possible motives.
Denji’s Life as a Devil Hunter
Denji’s life as a Devil Hunter is anything but peaceful. While he enjoyed his stint working as one, he often questioned himself. He was starting to realize that he was losing his grip on being human. Makima often preyed on this, who acted as his maternal figure. This led the boy to fall deeply more in love with Makima who was always there for him.
As the boy adjusted to his life, he never quite realized that he was living a lie. Denji enjoyed his time with Aki and Power. He even developed a close bond with them despite their rocky start. They became part of his family and he often hung out with them. Hard not to when they were living together after all! Still, he was thankful for everything that came into his life. He was having a normal life just as he always wanted. He had a hot girl to hopefully get it on with and ate a good breakfast every day.

So, when everything came crashing down, he didn’t know how to react.
The Fall of Denji
Most of the events that happened to Denji were planned by Makima. Ever since their first meeting, the latter had already sunk her fangs into the former. It was a matter of time before Denji finally broke. She had used Aki and Power to mentally cripple Denji. By making the latter kill Aki, one of his best friends, he was sent into a downward spiral. Right into Makima’s arms. After Makima gave him an escape, she pushed for his collapse further. After having Power visit, she killed the latter in front of him. These events forced Denji to confront reality.
The act broke Denji’s spirit and which ultimately led him to fall. Having regressed to baser instincts, he let his subconscious drive. This meant Pochita was now driving the wheel, exactly as Makima wanted. The latter moved to try and subjugate Pochita while in his Chainsaw Devil state.

The Return of Denji
Even though Denji was hiding in his subconscious, Pochita was able to reach out to him through Power. The little Chainsaw Devil was able to come into contact with the Blood Devil. It convinced her to bring Denji back. After forcing Denji to promise to find her again, Denji was brought back out to the driving seat. He lamented his inability to become normal. Faced with the consequences of his and Makima’s actions, he developed the courage to face her one last time.

This time, he was disillusioned by Makima’s tricks. After realizing that his life had been a lie, he made a plan to outsmart the Control Devil. He banked on the fact that she only saw Pochita in his heart and never saw him as Denji. This gamble paid out for him as he was able to incapacitate Makima and chopped her to pieces.
Conclusion
Due to Makima’s contract, it was impossible to kill her by conventional means. Killing her would kill one random member of Japan’s populace instead. Chopping her up doesn’t mean that she was dead. According to Denji’s mentor, people were dying as Makima stayed dismembered. Taking upon another gamble, Denji had asked his mentor to trust him with his plan. He was going to eat Makima as a sign of his “love”. This meant that despite it all, Denji still chose to love Makima. It was through this that Makima’s contract was bypassed, and she died once and for all.
What Happened to Denji in the End?
Part 1 ended with Denji finally attending high school. Before that, he was forced to look after Makima’s reincarnation: Nayuta.
What Happens Next for Denji?
Part 2 of Chainsaw Man has already been released since July 2022. In this new series, we see Denji put to the side in favor of the new protagonist. So, we will have the new questions answered according to the new chapters.
Frequently Asked Questions
Does Denji still have Pochita?

As long as Denji has his heart, he will still have Pochita.
Will Denji Appear in Chainsaw Man Part 2?

As of Chapter 102, Denji has officially returned to the manga.
Is Denji still a Chainsaw Man?

Recent events in Part 2 show that Denji is, indeed, still the Chainsaw Man. He has even taken it upon himself to prove to the world that he is Chainsaw Man.