A group of time - traveling historians. They accidentally cross paths with Addie during one of their trips. They are fascinated by her and want to study her unique situation. This could bring in elements of different time periods as they try to figure out how Addie has survived for so long. Their presence could also put Addie in danger as they might accidentally expose her to the wrong people.
One idea could be exploring Addie's encounters with different historical figures in more depth. For example, how she influenced or was influenced by them during specific events. Another could be a story where she tries to find a way to reverse her curse in a new and unexpected way, perhaps with the help of a modern-day character who has some unique knowledge or ability.
A young Martian inventor could be a great addition. This character could create unique gadgets and machines that help the protagonists in their adventures. For example, a flying device that can travel at high speeds across Mars.
A mysterious traveler passing through the town could be a new character. This person has seen many strange things in their travels and is not afraid of Edward. In fact, they see his potential and encourage him to leave the town and see the world.
A healer character could be added. This healer could be the one who discovers a hidden power within the apprentice that could change the course of their journey. Another potential character could be a mysterious traveler. This traveler has seen many different worlds and has knowledge that could either help or hinder the apprentice.
In a Space Jam: A New Legacy fanfiction, a character like a time - traveling video game historian could be introduced. This character knows all about the history of video games and basketball in the digital realm and can use this knowledge to help the Tune Squad. Another new character could be a shape - shifting blob from a gooey video game. It can transform into different objects or even other characters to help the team in various ways. Also, a talking basketball that has its own mind and can offer advice and pep talks to the players would be an interesting addition.
One common theme is love. Given Addie's long life and her relationships, many fanfictions explore different kinds of love she experiences. Another theme is her struggle with immortality. Writers often delve into how she copes with always being alone in the long run.
A new character could be a mortal who has somehow gained the ability to see through the Mist completely. This mortal is on a mission to expose the world of demigods and the gods themselves. Percy has to either convince this mortal to keep quiet or find a way to make them forget what they've seen, all while dealing with the chaos this person is causing in the demigod world.
A young witch from a rival coven could be added. She might be initially antagonistic towards Ciel and Sebastian but later form an uneasy alliance when a greater threat emerges. She could bring in new magical elements and challenges to the story.
An old and wise Pokemon sage. This character could live in a hidden forest and have knowledge about ancient Pokemon powers. They could play a role in either helping Pokemon Hunter J find redemption or in protecting the Pokemon from her. For example, they could give J some cryptic advice that makes her think twice about her actions.
A vampire scientist. This character could be researching ways to create a new type of vampire that is immune to the weaknesses of traditional vampires, like sunlight or silver. Their experiments could cause a stir among both the vampire and lycan communities.