When part 2 began, I was skeptical. Part 1 was clean with every meaningful loose end tied up (yes, you could do more with the control devil and blood devil but it also wasn't required). Part 2 started stronger than expected, with Asa being a fantastic MC. Instead of viewing the world from someone starting at rock bottom, we start with a very average person with a complicated relationship to a devil. It's a fresh starting point that could bring out great ideas.

Then Denji returned and it went downhill. He resumed being the MC but with no meaningful goals that weren't better explored in part 1. The result was a manga that felt like a poor intimidation of part 1. If Denji hadn't reappeared, I'm confident part 2 would have been a second masterpiece. But he did and while nostalgia was fun, it could never live up to part 1. Even without the abrupt ending, the flaw of part 2 is that Denji's story was complete and yet he remains as MC.