One interesting headcanon could be about the backstories of the Servants. For example, there might be a headcanon that a certain Servant had a secret friendship in their past life that influenced their character in the game. Another could be related to the magic system in the Fate Grand Order universe, like a unique way of casting spells that isn't shown in the main story.
Well, a popular headcanon is that Percy can see the memories of the ocean. So in fanfiction, he might touch an old piece of coral and suddenly be flooded with images of ancient sea battles or long - lost civilizations. Also, some think that Annabeth has a fear of heights that she hides really well because she doesn't want to seem weak. As for Grover, perhaps he has a family of satyrs in a hidden grove that he secretly visits and they tell him old satyr tales that he then uses to his advantage on quests.
I like the headcanon where Annabeth is a master of disguise. In fanfiction, she can blend into any crowd, not just because of her intelligence but also because she has some magical items that help her change her appearance. It makes her even more resourceful on quests. Grover, on the other hand, has a headcanon where he can grow plants with just a touch. So if they're in a barren area, he can create a little oasis for them to rest in. This shows his connection to nature in a more powerful way.
One idea could be that Neville Longbottom is secretly a powerful wizard all along but has been suppressing his power due to self - doubt. Another could be that the Hogwarts portraits have their own little society and gossip network within the castle walls. And a third one might be that Hagrid has a secret family of magical creatures in the Forbidden Forest that he takes care of.
Ninjago might be interested in Ninjago fanfiction because it could offer new ideas for their own battles and challenges. The fanfiction world is full of creative minds, and there could be some brilliant strategies or concepts in those stories that they could adapt. Also, it could be a form of entertainment for them, just like how we enjoy fictional stories about other things.
If Ninjago watches Ninjago fanfiction, they could get a whole new perspective on their own world. Some fanfictions might show them in different relationships or situations that they hadn't considered before. It could also inspire them to do things differently in their own adventures. For example, if a fanfiction has a really clever solution to a problem they've faced, they might think about using a similar approach in their own world.
It can add more depth to minor characters. For example, by creating headcanons about characters like Lavender Brown, we get to see a side of the Hogwarts student body that wasn't fully explored in the original. It gives them more personality and backstory.
The Fate Grand Order Headcanons Novel can expand the game's lore in multiple ways. It can provide more details about the Servants' Noble Phantasms, their origin, and how they function. It might also offer insights into the world outside of the main story's events, such as the daily lives of ordinary people in the Fate Grand Order universe. Moreover, it could introduce new concepts related to the magic and technology in the game, which helps to create a more complex and immersive world for the players.
One idea could be a story where Zane and Pixal go on a mission together to a new, uncharted land in Ninjago. They face various challenges that test their relationship and their individual skills. Maybe they encounter a new type of technology that Pixal has to figure out while Zane defends them from the local threats.