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 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.
Yes, it is. The manga has a perfect balance of action, drama, and philosophy. The themes explored are profound, and the character growth is very satisfying.
There probably are. Fanfiction writers often love to mash up different universes. In such a fanfic, Naruto could bring his chakra - based powers and blend them with the principles of alchemy from Fullmetal Alchemist. Maybe he'd use his Rasengan in a new way by incorporating alchemical transmutation circles. It would be a wild and creative concept.
One great fanfiction could be about Izumi's backstory before she became an alchemist. It might explore her early training days and the challenges she faced. For example, a story could focus on how she overcame the difficulties of learning complex alchemical theories without proper guidance at first.