One common theme is redemption. Since Charlie is all about rehabilitating sinners in Hazbin Hotel, often in these fictions, the male reader might be a character who is also in need of redemption, and Charlie helps him on that journey. It's a way to explore the idea of second chances.
Love against all odds is also a major theme. Hell is not exactly a place known for love and kindness, but in these fictions, Charlie and the male reader find a connection. It shows that love can exist even in the most unlikely of places. Their relationship has to overcome many obstacles, like the nature of the other demons in Hell and the male reader's own insecurities or differences.
Redemption is a common theme. Charlie is all about redeeming sinners in Hell, and an OC can either be a part of that mission or a hindrance. Another theme is self - discovery. The OC, through their interactions with Charlie, may learn more about themselves, their place in Hell, and their own potential for change. And of course, friendship or love can be a theme too, as they build a connection with Charlie.
Another theme is growth. Fanfictions often show Charlie and Vaggie growing both individually and as a couple. For example, Charlie might learn to be more assertive in her relationship while Vaggie might become more open - minded, and these changes are usually related to the challenges they face together in running the hotel or dealing with other demons.
Romance can also be a common theme in 'hazbin hotel male reader fanfiction'. The male reader might fall in love with one of the female characters in the Hazbin Hotel universe. This could involve a lot of emotional development and relationship building. Also, redemption is a theme that shows up sometimes. The male reader could be part of a story where he helps in the redemption of the sinners in the hotel, which ties in well with the overall concept of the show.
One common theme is the power dynamic. Alastor being a powerful demon and the reader usually being a more ordinary (by Hell's standards) character. Another is the idea of redemption. Maybe the reader tries to 'redeem' Alastor in some way. Also, there's often a theme of mystery, as Alastor has many secrets.
Power and temptation are common themes. Lucifer is a powerful figure, and his interactions with the reader often involve him using his power to either tempt or protect. Another theme is the exploration of the afterlife. Since it's set in Hell in the Hazbin Hotel universe, the fanfiction can delve into what it means to be in Hell and how the reader fits into that world.
Redemption is also a frequent theme. Given the setting of Hazbin Hotel, the idea of Adam finding redemption through his relationship with the reader is quite popular. It could involve him learning about love and acceptance in a new way.
Another theme is redemption itself. Charlie is always trying to redeem sinners in Hazbin Hotel, and in the fanfics, Alastor's character can be a part of that journey. Maybe she tries to redeem him, or he helps her in her mission in unexpected ways.
Redemption is a common theme. Since the Hazbin Hotel is about rehabilitating sinners, many fanfics have the reader character going through a journey of self - redemption or helping other characters with their redemption. For example, in some fanfics, the reader might befriend a character who has a lot of guilt and help them come to terms with their past.
One great piece of 'Hazbin Hotel Charlie x male reader fanfiction' can be found on Archive of Our Own. It's titled 'In the Arms of an Angel'. It has a really sweet plot where the male reader character helps Charlie deal with the challenges of running the hotel in Hell. The relationship development between them is very well - written.
In Hazbin Hotel Charlie x OC fanfiction, the OC can bring fresh perspectives. Charlie is often associated with her mission to redeem sinners in Hell. An OC might challenge this idea or support it in unexpected ways. The OC could be a demon who has a more cynical view of redemption, which could create tension. On the other hand, they could also be an angel - like figure in Hell (even if that's an oxymoron in the context) who helps Charlie see new ways to approach her goal. Moreover, the fanfiction can play with different art styles if it's accompanied by illustrations. Some may depict Charlie and the OC in a more cartoonish style similar to the original Hazbin Hotel art, while others might go for a darker, more detailed aesthetic.