One common theme is the struggle between good and evil. The angel, with their shotgun, might be fighting against demons or other dark forces, representing the battle for the greater good.
You can try some popular fanfiction websites like Archive of Our Own (AO3). It has a large collection of fanfics, and you might be able to find some great 'angel with a shotgun supernatural fanfic' there.
One idea could be to explore the backstory of the angel. Maybe they were once a high - ranking celestial being who fell from grace but still holds on to their sense of justice, which is why they carry the shotgun. Another idea is to have the angel team up with a human hunter in the supernatural world, and they face off against demons that are causing chaos in a small town.
The main character is the angel, but there could be a mentor figure, perhaps an older and wiser angel who taught the main angel how to use the shotgun in the first place. And then there might be a character who represents the human world, a simple person whose life gets intertwined with the angel's mission. This person could be a source of inspiration for the angel to keep fighting with the shotgun.
A great plot idea could be that the shotgun the angel has is actually a cursed weapon. The angel has to figure out how to break the curse without losing the weapon's power. Or perhaps the fanfic could center around the angel's relationship with other celestial beings. They might not approve of the angel's violent methods with the shotgun and try to stop the angel from using it. This could lead to a conflict within the celestial realm.
To make it more engaging, you should develop the characters well. Give the angel a complex personality. Maybe they're conflicted between their angelic nature and the violent means of using the shotgun. Also, introduce some interesting side characters. For example, a young seer who can see the future but is terrified of the angel at first. Then, build up the plot with lots of twists and turns. Just when the readers think they know what's going to happen, throw in a surprise like the angel's shotgun being stolen by a demon and they have to find a way to get it back without their main weapon.
Yes, there might be. Some fanfiction writers like to incorporate unique and edgy concepts like 'angel with a shotgun' into their Harry Potter - inspired stories. It could add an interesting and unexpected twist to the magical world of Harry Potter, perhaps creating a new kind of character or a different take on the battle between good and evil.
It could be a protector. Just like how angels are often seen as guardians, the 'angel with a shotgun' in Harry Potter fanfiction might safeguard the characters from dark wizards or other threats. The shotgun could be a symbol of a more direct and forceful approach to protection compared to the usual magic used in the series.
I'm not sure specifically as I haven't read this particular fanfic. But generally, it might be about a character named Harry who is portrayed as the Angel of Death in the context of the Supernatural universe. Maybe it involves Harry having powers related to death, like being able to reap souls or having some sort of connection to the afterlife.
Another theme is the idea of family. In Supernatural, Sam and Dean have a strong brotherly bond, and in Dark Angel, Max has her own 'family' among the transgenic group. In crossover fanfic, these family concepts often collide and merge. For example, the transgenic might be seen as a new kind of 'family' by the Winchesters or vice versa. It's about how different forms of family support and protect each other in the face of danger.