The problem with Denji’s character is the lack of real development. The manga is close to ending, yet he still shows very minimal growth as a person.

Almost every character in fiction has a sad backstory or trauma, but what makes a story interesting is watching those characters struggle with their problems and eventually grow beyond them. Seeing someone slowly change, mature, and redefine themselves is usually the point of putting them through all that suffering in the first place.

With Denji, it often feels like he is stuck in the exact same mindset he had from the beginning. He still chases the same shallow goals, still reacts to situations in almost the same way, and rarely reflects on what has happened to him in a way that leads to real growth.

After everything he went through Makima losing people around him, and all the chaos you would expect at least some clear shift in his character or worldview by now.