In fanfics, Admiral Kizaru's power can be highly exaggerated. His Pika Pika no Mi ability, which allows him to move at the speed of light, can be made even more potent. Writers might make him capable of creating stronger light - based attacks or having better control over his speed. For example, he could be shown to split into multiple light - clones more easily and use them in more complex battle strategies.
Another theme is loyalty. Kizaru is often part of a group, and fanfictions explore his loyalty to his comrades. There could be stories where he has to choose between following orders and doing what he believes is right for his friends. This creates interesting moral dilemmas within the story.
One idea could be a crossover with the One Piece world and the Naruto universe. Kizaru could end up in Konoha and his light - based powers would be a mystery to the ninja there. They might mistake his abilities for some new form of ninjutsu.
Fanfic writers often play with Admiral Kizaru's power in unique ways. They might give him the ability to manipulate light in different forms, such as creating solid light constructs. These constructs could be used as shields or additional weapons. Also, his power over light could be extended to include the power of illusion, where he can create false images of himself to confuse his enemies. This adds a new layer of complexity to his character and his battles.
First, decide on the world or character you want to crossover with Kizaru. For example, if it's the Star Wars universe, think about how Kizaru's light - based attacks could be compared to lightsabers. Then, come up with a plot. Maybe Kizaru is sent to a different galaxy and has to find his way back home while getting involved in the Galactic Civil War.
There's a fanfiction called 'Kizaru and the Lost Treasure'. Here, Kizaru stumbles upon a map that leads to a long - lost treasure. Along the way, he has to face off against other pirates who also want the treasure. His speed and light abilities give him an edge in the battles that ensue.