The Chainsaw Man fandom recently came up with a lot of theories because of the Death Devil plot twist, and one that has become quite prevalent is how she could have been involved in Makima's defeat in the first part of the manga. That is because Kishibe, right after Denji's victory over her, mentions that he managed to best her by eating her remains, which is something that could have been established by Death in the villain's contract.
With the recent twist in the Chainsaw Man manga, a lot of people have theorized that this means that perhaps Death had put a clause in Makima's contract for her eventual devil. While it is impossible to confirm if that is the case, it would be interesting to see that the former Control Devil had placed a clause where only the Chainsaw Devil could permanently kill her by eating her, which would fit with her devotion.
Disclaimer: This article is speculative and reflects the writer's opinion.
Explaining how Makima's defeat in Chainsaw Man could be connected to the Death Devil

Right after Makima is defeated and eaten by Denji, Kishibe tells the protagonist that he wonders if there was a clause in the contract of the Control Devil that allowed them to win at the eleventh hour. While it is difficult to predict at the moment, there is an argument to be made that Makima had a clause in her contract made by the Death Devil.
Some fans have pointed out how the Death Devil, formerly known as Fami, can control crows and seems to be an extension of herself, which has been present since the days of the first part of the manga. These crows are at the cemetery when Denji and Makima are fighting, which could mean that Death was present to witness the end of her sister.
Moreover, it would make sense for someone like Makima to have an element in her contract where she would be allowed to be eaten by the Chainsaw Devil, which is consistent with her character and adoration toward Pochita. This is an element that could connect both parts in a stronger manner while perhaps providing even more context for the former Control Devil.
The ramifications of the Death Devil twist

The twist of Fami being the real Death Devil has taken the Chainsaw Man fandom by storm and has led to a lot of different interpretations of what the story could be moving forward. Some fans have come up with the theory that if she simply lied about her identity, she could also be lying about her motivation and goals in the story, especially regarding the potential apocalypse.
This is something that could connect her to Makima and the latter's actions in the first part, while also providing an explanation regarding what she wants to do with Denji and Yoru. Therefore, this twist is bound to be monumental for the conclusion of the second part and the story as a whole.
Final thoughts
There is the possibility that, as per Kishibe, Makima had an element in her contract that could have been established by the Death Devil in Chainsaw Man. It would provide more context for the character's defeat and also connect both parts in a stronger manner.
Related articles:
- Yoru and Asa's switch in Chainsaw Man chapter 200 teases this theory as true
- Chainsaw Man chapter 200 highlights Denji's influence on Asa (& it spells their romantic doom)
- Chainsaw Man chapter 200 all but confirms that Denji and Asa won't have a happy ending
- Chainsaw Man chapter 200: Denji and Asa's antics set up a fight with Fakesaw Man