Chainsaw Man is one of the most original ongoing manga series currently running, so when it incorporates elements from other popular titles like Naruto's Kurama, creator Tatsuki Fujimoto gives them his own ridiculous spin.
In Naruto, the titular character's parents seal one of the Tailed Beasts, the Nine-Tails named Kurama, inside of their son to prevent the demon from causing further havoc on the Hidden Leaf Village. They also hoped that Kurama would later help Naruto defeat Tobi, the villain who had unleashed Kurama on their home to begin with.
Regardless of whether Kurama helps Naruto achieve this goal or if Naruto ever faces Tobi, the Nail Tails demon does provide Naruto with incredible power that manifests in different ways throughout the series, the most compelling ones being his many transformations. While each one is powerful and awesome in its own right, the most compelling transformations are those that allow Naruto to take on the form of Kurama.
Chainsaw Man essentially takes both the reason why the series' protagonist, Denji, gets a devil "sealed" inside of him and how Denji's transformation manifests as a result of this act of "sealing" to an absolutely ridiculous extreme. It begins when Denji tries to pay back his late father's debts by hunting devils with his own little devil, a cute puppy-like creature with a tiny little saw for a nose named Pochita. Unfortunately, Denji can't pursue his dream of just living a normal life because of how much time and effort it takes to pay off these debts. So when Denji literally gets ripped to pieces by a horde of devils, Pochita, who had both loved hearing Denji talk about his dreams and wanted his master to pursue them, saves him by literally becoming his heart.
This selfless act not only "sews" Denji's torn body back together, but bestows upon him an incredible power. Upon entering his body, Pochita's rope that engaged the saw on his nose now hangs from Denji's chest. And when someone pulls the rope, Denji's head and arms transform into actual saws that he employs to slice and dice his enemies to smithereens. But using the saws for a prolonged period of time can cause them to fully or partially retract, and only drinking blood will bring them back to full functionality. But, of course, being as resourceful as he is, Denji later realizes that he can drink the blood spilling from his victims to continue fighting.
Another stunning correlation between Naruto and Chainsaw Man is how Denji perceives Pochita inside of him. In Naruto, the young shinobi would interact with Kurama in an alternate plane where Kurama can be seen locked behind a massive cage. In Chainsaw Man, Denji's interactions take the form of haunting nightmares that are much more disturbing. Behind an eerie door, covered with some sort of material that serves as patches, one of Pochita's eyes can be seen peering out ominously from a small hole.
All these comparisons between Naruto and Chainsaw Man aside, the latter appeals to an ever-increasing number of readers because of creator Tatsuki Fujimoto's audacious originality. This is made evident by the plethora of devils and devilmen that devil hunters come across throughout the series, along with the creative ways in which these hunters are forced to form contacts with the creatures to gain terrifying abilities. Fujimoto might incorporate elements from other manga, but he does so without sacrificing any originality, all while blending the right amount of gratuitous gore with dirty humor and quirky romance.