One popular theme is the exploration of Greed's complex character in the crossover setting. Since he has his own unique set of desires and moral ambiguities, it often leads to interesting storylines where he interacts with other characters from different universes or story arcs within the Fullmetal Alchemist world. Another theme could be the power dynamics. How does Greed's power compare and interact with the powers of characters from the crossover? It can create some intense battle or cooperation scenarios. Also, the theme of redemption sometimes shows up. As Greed is a character with a lot of 'greed' (obviously), his journey towards possible redemption or further fall into his vices can be a fascinating plot point in fanfictions.
A fanfiction might focus on a romantic relationship between Greed and the OC. Given Greed's nature, it would be a complex relationship. The OC could be initially attracted to Greed's boldness and power, but then has to deal with his flaws. Greed, on the other hand, might find the OC's purity or uniqueness captivating, and they have to navigate through the dangerous world of alchemy and power struggles while also dealing with their growing feelings for each other.
The plot could involve the OC being a alchemist on a quest for a powerful alchemy item. Greed, sensing an opportunity for himself, joins the OC. Along the way, they encounter various enemies and obstacles. For instance, they might have to face off against other homunculi who don't want Greed interfering in their plans. The relationship between Greed and the OC could start off as a simple partnership but evolve into a deep friendship or more as they rely on each other to survive.
One popular character is Scar. His unique brand of alchemy and his backstory of revenge can create some really intense crossovers. Edward Elric, as mentioned before, is always popular. He can be paired with characters from other series to have some amazing adventures. Hohenheim is also a character that shows up in a lot of crossovers. His long life and his connection to the Homunculus can add a lot of depth to crossover stories. He can interact with other powerful or long - lived characters from different universes in very engaging ways.
Greed crossover fanfiction often combines elements of different fictional universes with the concept of 'greed' as a central theme. For example, it might merge characters from a fantasy world known for its gold - loving dragons with characters from a modern - day corporate - greed - inspired setting. The 'greed' can drive the plot, like characters competing for a powerful and coveted item that exists in both fictional worlds.
There could be a fanfiction that combines the 'Hunger Games' with a world based on ancient mythology. In the 'Hunger Games', the Capitol's greed for control and entertainment is prominent. When crossed with a mythological world, like the Greek gods' greed for worship and power, it could lead to an interesting story. Also, a crossover between 'Sherlock Holmes' stories and a world of high - tech thieves. Sherlock's pursuit of truth against the thieves' greed for valuable items would make for an exciting fanfiction.
Edward could be a great character to pair with Female Envy. Their interactions would be full of tension and conflict, given their different natures. Edward's strong sense of justice and Envy's devious ways would create a lot of interesting scenarios.
It's hard to say without reading it specifically, but it could be Naruto himself dealing with the concept of greed in some way. Maybe he has to face an enemy who is extremely greedy and he has to find a way to stop them without succumbing to the same sin.
First, know the characters well. Understand Greed's personality, his desires, and his powers in FMA. Then, research the other fandom you want to crossover with. Next, create a unique and engaging plot that combines elements from both worlds in a seamless way. For example, if it's a crossover with a fantasy world, think about how Greed's alchemical nature would interact with magic. Don't forget to develop good character relationships and let the story flow naturally.
One idea could be that Greed finds himself in an alternate universe where the rules of alchemy are slightly different. He could then try to adapt and use this new knowledge to his advantage, all while facing new and unexpected enemies. Another plot could involve Greed teaming up with characters from another fandom in a quest for a powerful and mysterious object that exists in both worlds.