Honestly speaking, I didn't find the work very exciting, and I also believe it suffers from a lack of originality. The characters often use the typical phrases from the series, like "Once again, I couldn't achieve anything" or "I don't want to burden anyone anymore; I want to become stronger." Even the dynamics concerning the relationships between the characters follow well-worn patterns, such as the character seeking revenge who eventually befriends one of the protagonists after realizing a misunderstanding, or the character struggling to express and understand human emotions, learning to do so thanks to another character. All of this, of course, happens without any meaningful additions that could make it somewhat interesting.
Some characters find themselves in situations triggering their development, but it often seems as if this primarily serves to allow the character in question to overcome a specific situation without, except in rare cases, witnessing any genuine change leading to character growth, which we only see a bit of towards the end.
The author also attempts to delve into elements related to the world of demons in the work, but, even in this case, I must say that the demon cosmology and their culture don't bring anything interesting along with them.
Regarding the drawing style, I would describe the author's style as a well-executed but somewhat mundane one that effectively accomplishes its purpose. However, I must also mention that, at times, some onomatopoeias were so large that they hindered the comprehension of the scene in the panel.
Additionally, I found the design of some demons quite appealing. I particularly appreciated the brief part of the work that brought a Western atmosphere with it, complete with demons dressed as cowboys.