The novelty of it. Tickling is not a common theme associated with Alastor usually. So when it's explored in fanfic, it gives a fresh perspective on his character.
One popular 'alastor tickle fanfic' is 'The Ticklish Radio Demon'. It has an interesting plot where Alastor gets into some comical situations involving tickling. It shows a different side of his character in a light - hearted way.
In this fanfiction scenario, Alastor's reaction would likely be a mix of curiosity and amusement. He'd be curious about what exactly draws this female to be such a big fan of his. Is it his power? His style? His radio shows? He'd be amused by her enthusiasm, seeing it as a form of entertainment. However, he'd also be cautious. He doesn't trust easily, and this female fan would need to prove herself worthy of his time and attention. He might test her loyalty or knowledge about him in various ways, like quizzing her on his past deeds or his preferred methods of causing chaos.
Another theme might be the ears as a source of power or connection. Maybe in some fanfics, his ears are related to his ability to sense things or communicate in a special way. It could also be that the ears are a focus in a story about Alastor's transformation or evolution, like how they change as he gains more power or experiences different things.
One common theme could be emotional pain. Maybe Alastor is betrayed by someone he thought was a friend, which causes him to experience deep emotional distress.
Redemption is also a big theme. Since Charlie is on a mission to redeem souls, sometimes Alastor gets involved in this journey in the fanfics, either helping or hindering. And their relationship development is another key theme. How they grow to understand each other better over the course of the story is often explored in these fanfics. For example, in some fanfics, Alastor slowly starts to see the value in Charlie's ideas due to their continuous interactions.
One common theme is power struggle. Since both Alastor and Vox are powerful characters, many fanfics explore who is more powerful or how they balance their powers when they interact. For example, in some fanfics, they compete for territory or influence in their fictional realm.
The dark and mysterious nature of Alastor makes for great storytelling. Fanfic writers can take this and run with it, creating stories that range from action - packed adventures to deep, emotional character studies. This versatility is what makes alastor fanfic so popular.
One common theme is identity. The daughter often struggles to define herself apart from her father, Alastor. She has to figure out who she is on her own terms.
One idea could be a story where Lucifer and Alastor have to team up to deal with a new threat to Hell. Maybe a powerful demon from another realm is trying to take over, and they have to put aside their differences. They could start off not trusting each other much, but as they face challenges together, they begin to respect one another's abilities.