In some fanfictions, it could be a character from another magical school. Like a girl from Beauxbatons or Durmstrang. She might have met Harry during an international magical event and they've been secretly seeing each other ever since.
Maybe it's a new character created specifically for the fanfiction. A girl from a far - off region who Ash meets during one of his journeys. She could be a powerful trainer or have some special abilities that draw Ash to her, and they start a secret relationship.
It could be Misty. They have a long - standing relationship in the Pokemon series. They've traveled together and shared many adventures, so in a fanfiction, it's not a stretch to imagine her as a secret girlfriend.
Another possibility is that it's a Pokémon in human form, which is a common trope in some fanfics. This Pokémon - turned - human could have fallen in love with Ash during their adventures together, and now they have to keep their relationship a secret from the world of Pokémon and humans alike.
It could be a Muggle - born witch who he meets outside of Hogwarts during the summer holidays. She's not part of the typical wizarding society he's used to, so they keep it a secret as it's an unusual situation for a wizard like Harry to be involved with a Muggle - born in such a way.
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.
There are also some fanfictions where a completely new character is introduced as Naruto's secret girlfriend. This allows the writer to create a unique story line and explore different dynamics that are not bound by the pre - existing characters and relationships in the Naruto universe.
Educate yourself about transgender issues. Read books, watch documentaries. This way, you can understand her experiences better. Also, be her advocate. Stand up for her when she faces discrimination. For example, if someone makes a rude comment, correct them.
His secret girlfriend could be in a difficult situation herself. Maybe she's a demigod with a dangerous family or past. Percy is trying to help her while keeping their relationship a secret. This could involve them sneaking around to meet, sharing secret glances in public, and having to communicate in coded ways. It would create a really interesting and suspenseful plot.
Often, she is depicted as strong - willed. Since Naruto is a very determined character himself, having a girlfriend with a similar trait can create interesting story arcs where they support and challenge each other.