If Naruto was a gladiator, he'd be a force to be reckoned with. His speed and agility from his ninja training would make him a top - tier gladiator. He could use his shadow clones to distract his opponents while he attacks from another angle. His Rasengan could be his finishing move in the arena, much to the amazement of the crowd.
A cool idea in Naruto - Greece fanfiction could be the use of chakra in the context of Greek magic. Chakra, which is the life force in Naruto, could be equivalent to the mana or power that Greek mages might use. The ninja from Naruto could interact with Greek sorcerers, and they could learn from each other's powers. For instance, Naruto might learn some unique spell - casting techniques from a Greek mage, while the mage could be interested in the way Naruto manipulates chakra.
Well, in a Naruto in Ancient Greece fanfic, Naruto could be a Spartan warrior. He'd use his ninja skills in the Greek battlefields. His shadow clones could be like an army of Spartans, confusing the enemies. His Rasengan might be seen as some sort of divine power. And he'd probably have to face off against Greek monsters too, using his quick thinking and ninja training.
He could have adventures like battling mythical creatures. For example, fighting the Minotaur in the labyrinth. Maybe he'd also encounter the gods and goddesses and get involved in their power struggles.
In ancient Greek mythology, the names of the 72 gods included Zeus, Hera, Hades, Persephone, Poseidon, Athena, Apollo, Artemis, Ares, Aphrodite, Hephaestus, Hestia, and so on.
Since we don't have a lot of information, he might have been a tourist visiting Greece. Tourists can unfortunately be victims in some cases. Or he could be a local worker, like a fisherman or a construction worker, who got into a bad situation.
One great 'Percy Jackson Ancient Greece Fanfiction' is 'The Lost Hero's Quest in Ancient Greece'. It has an exciting plot where the characters are plunged into a forgotten part of Ancient Greek mythology. The author does a wonderful job of weaving in the familiar elements from the Percy Jackson series with new and unique twists from Ancient Greek lore.
You can try looking on some popular fanfiction websites like Archive of Our Own (AO3). There are often many works in different categories, and you might find Greece x Reader fics there. Just use the search function and type in relevant keywords.
One common theme is time - travel. Since Percy is from a modern - day setting in the original series, sending him back to ancient Greece allows for all kinds of interesting scenarios. Another theme is the interaction with the Greek heroes and gods. Writers often explore how Percy would interact with the likes of Achilles or Apollo.