Another plot could be that they are both after the same rare and valuable treasure. At first, they compete, but then they realize that the real threat is a third party trying to steal it from both of them, so they join forces to protect it and split it in the end.
One idea could be that they form an unlikely alliance to take over a powerful underworld organization. They start off distrusting each other but gradually realize they can achieve more together.
One idea could be a story where Crocodile and Doflamingo have to team up against a common enemy that threatens their own interests in the New World. Maybe a new and powerful pirate crew that is disrupting their business operations. Another plot could involve a past encounter they had that changed their relationship, like a time when they were both rookies and something happened that led to a grudging respect for each other.
A possible plot could be set in an alternate universe where Doflamingo is not a villain from the start. He and Nami meet on an island where they both have a common goal, like finding a rare treasure. As they search for it, they start to bond over their shared love for adventure and discovery, and a romantic relationship begins to form between them.
For Doflamingo, you can focus on his flamboyant and unpredictable nature. Show his sadistic side in how he deals with enemies, but also explore his more vulnerable moments, like when his plans are thwarted. For Crocodile, emphasize his cool and calculating demeanor. Let his past failures fuel his actions in the fanfiction, like his determination to regain his lost status. Maybe show how Doflamingo's chaos sometimes clashes with Crocodile's order.
The power combination. Crocodile's sand - based powers and Doflamingo's string powers can create really cool and unique fight scenes in fanfiction. For example, in some stories, they use their powers together to take on a much stronger foe.
One idea could be a story where Law and Doflamingo are forced to team up due to some external threat to the One Piece world. They initially clash because of their very different moral compasses but gradually come to understand each other's motives. Another plot could involve a time - travel scenario where Law goes back in time and has to deal with a younger Doflamingo, trying to change the course of events that led to Doflamingo's tyranny. Or perhaps a story where they are both stranded on a mysterious island and have to rely on each other's skills to survive, all while Law is constantly tempted to take Doflamingo down.
A plot could involve Doflamingo having some sort of debt to Law from their past that he doesn't remember clearly. Law decides to cash in on this debt which leads to a series of events where they have to interact more closely than they ever wanted. It could also be a story about a power struggle between them, not in a physical sense but in terms of influence in the pirate world.
Often, these fanfictions highlight their power and influence. Doflamingo's devious nature and Crocodile's calm and calculating demeanor are usually well - portrayed. For example, in some, they might be shown as rivals vying for control in the underworld of the One Piece world.
Another plot could revolve around an OC who is a former victim of Doflamingo's cruel rule. This OC could be on a quest for revenge. They might start by gathering allies who were also affected by Doflamingo and then plan a elaborate scheme to take him down. Along the way, they could face many challenges and obstacles set by Doflamingo and his loyal followers.
Power is a common theme. Both Doflamingo and Crocodile are powerful characters in their own right, and fanfics often explore how their powers interact when they are together. For example, in some fanfics, they might compete to show who is more powerful.
One popular 'One Piece Crocodile x Doflamingo fanfiction' might be 'The Unlikely Alliance'. It delves into their complex relationship within the One Piece universe, exploring how their powers and personalities could interact in unique ways.