It could be a character completely made up for the fanfiction. A young girl named Elara who has the power to communicate with animals. She and Percy met in the forest, and they kept their relationship a secret because Elara's power is seen as a threat by some in the story's world.
Another possibility is that his secret wife was an ordinary human at first. They fell in love in Percy's early days, before he became well - known. She's kept secret because Percy wants to keep her out of the dangerous world he often finds himself in. For example, she could work in a library, and they have a very normal - seeming relationship in private.
It could be a mark that represents his family or a long - lost heritage. Perhaps it's a crest that has been passed down through generations in his family but he has to keep it secret for some reason, like it might draw unwanted attention from certain enemies or factions in the story.
Perhaps the tattoo has a special meaning that he wants to keep private. It could be related to a personal journey or a relationship that he doesn't want others to interfere with. For example, if it's a tattoo related to a past love or a mentor who taught him a valuable but forbidden skill. The knowledge of the tattoo could expose these things and he wants to protect them.
The idea of Percy having a secret girlfriend in fanfiction can open up a whole new world of character development. If his girlfriend is a new character introduced in the fanfiction, she could have unique powers or abilities that complement Percy's. Their secret relationship could be a way to explore Percy's more private and vulnerable side, away from his usual heroic adventures.
Another possibility is that Percy is recruited by a secret organization that has discovered his demigod powers. They see his potential as a secret agent because of his combat skills, quick thinking, and ability to adapt in dangerous situations. In this fanfiction, he might have to work with other agents who are initially skeptical of his 'weird' powers but soon come to respect and rely on him.
In Percy and Artemis' secret relationship fanfiction, it often involves a lot of creative interpretations. Writers might explore how their different personalities interact. For example, Percy's adventurous spirit could contrast with Artemis' more reserved and goddess - like nature. This can lead to some really interesting storylines where they might have to keep their relationship a secret from the other gods and demigods, adding an element of mystery and danger to the story.
In some fanfictions, Percy might be depicted as Artemis' secret lover. Fanfiction allows for a lot of creative interpretations of characters and their relationships. However, in the original mythology and main series, this is not a canonical relationship.
The fanfiction could start with Percy and Luke realizing their feelings for each other during a training session at Camp Half - Blood. They share a secret glance that sets the whole thing in motion. Their secret relationship would be full of stolen moments, like when they meet by the lake at night.