One common theme is good vs. evil. The angel warriors and archangels often fight against dark forces. Another theme is redemption. Sometimes an angel or archangel has made a mistake and they strive to make up for it.
The theme of loyalty is also prevalent. The angel warriors are loyal to their archangel leaders and to their cause. In many fanfics, this loyalty is tested in various situations, which makes for an exciting read. There is also the theme of discovery, like an angel warrior discovering new powers or a new purpose in their existence.
Another one is 'Angel Warrior's Destiny'. This fanfic focuses on a young angel warrior who discovers his true power. Along the way, he meets different archangels who help him on his journey. The character development in this story is really well - done.
The theme of destiny also pops up. Is it Dean's destiny to have these archangel powers? And what is he supposed to do with them? Fanfics often explore these big questions in different ways.
One common theme is redemption. Given Archangel's complex past and his sometimes - dark actions, many fanfics explore his journey to make up for his mistakes. Another theme is self - discovery. He has to figure out how to fully control his powers and what his role is within the X - Men.
Another theme is their relationships with humans. For example, an archangel might form an unlikely bond with a human character, and the fanfic delves into how that relationship develops and affects both parties. It can be a romantic relationship or a more platonic mentorship - like bond.
One common theme is redemption. The broken angel often tries to atone for something or regain its former self.
One common theme is friendship. Despite their differences, they form a bond. Another is the idea of redemption. Kenny might be seen as someone who needs to be redeemed in some way, and the angel could play a role in that.
Love is also a fairly common theme. It could be love for the angel that drives the characters to seek vengeance. There might also be themes of sacrifice. The characters may have to sacrifice a lot in their quest to avenge the angel. For example, they might sacrifice their own safety or relationships. In addition, the theme of power often comes up. Whether it's the power the angel had, or the power the avengers need to gain to succeed in their mission.
Well, in 'buffu angel' fanfic, one common theme is redemption. Maybe the angel has made some mistakes in the past and is trying to make up for it. There can also be a theme of love, not necessarily romantic love but also love for humanity or other beings. The idea of protecting something or someone dear is also quite common. This could be related to the angel's role in the fanfic world. Additionally, the theme of transformation is often seen. The angel might transform physically or in terms of its personality as the story progresses.
One common theme is the struggle between good and evil. Since you have an angel representing good and a devil representing evil, there's often a battle of ideologies. Another theme is redemption. Sometimes the devil character is shown to be redeemable through the influence of the angel.
Power and its consequences can be a theme as well. The 'angel of slaughter' is likely to have a great deal of power. Fanfics might explore how this power affects the character, those around them, and the world they exist in. Does the power corrupt? Or can it be used for good despite its violent origin?