To write a compelling Leonardo in fanfiction, first focus on his existing traits. He's brave, so show him facing his fears head - on in new and unexpected situations. For example, if he has a fear of heights, put him in a situation where he has to climb a tall building to save someone. Also, explore his relationships. Maybe he has a falling - out with a close friend and has to work hard to mend it, which shows his loyalty and determination.
Well, a great plot could be Leonardo having to face his own inner demons in a very literal sense. In the fanfiction, his fears and insecurities could manifest as physical entities that he has to battle. This would not only be a test of his physical strength but also his mental and emotional stability. And also, perhaps a plot where Leonardo discovers a hidden power within himself that he has to learn to control, all while dealing with the chaos of the Kekkai Sensen world.
One plot idea could be that Leonardo and White get involved in a mystery together within the Kekkai Sensen world. They might have to uncover a secret organization's plot that endangers the city. Another could be a story where they go on a journey to find a lost artifact that has special powers related to their world. Maybe they start off not getting along but as they face challenges, they grow closer.
To develop their relationship in a fanfic, you can explore their emotional sides. Maybe White has some insecurities about her powers and how she fits in, and Leonardo can be there to comfort and support her. This creates an emotional bond. They could also have misunderstandings at first. For example, Leonardo might misinterpret one of White's actions as being malicious when she was actually trying to help. Working through these misunderstandings can strengthen their relationship and make it more complex and interesting.
One popular theme is the exploration of the unique abilities of the characters. For example, how they use their powers in different situations not shown in the original work. Another theme could be the relationships between characters. Whether it's the deepening of friendships or the development of romantic interests. Also, alternate universe scenarios are quite common, like a world where the kekkai sensen society operates in a completely different way.
One idea could be exploring the backstories of the minor characters in Kekkai Sensen. For example, you could write about the life of a random citizen in Hellsalem's Lot and how they deal with the chaos. Another idea is to create an alternate universe where the main characters have different powers or personalities. Maybe Leo has the power to control time instead of his usual ability.
One idea could be a story where Chain and Leo have to team up to solve a mystery in the hidden world of Hellsalem's Lot. They might start off not getting along well due to their different personalities, but as they face various challenges together, they gradually learn to trust and rely on each other.
The Kekkai Sensen anime is known for being quite faithful to the manga. It maintains the original story and characters well. Though there are some creative adjustments made to make it more appealing on screen, they are mostly in line with the manga and fans tend to like them.