A new type of sea nymph who has the ability to change the color and texture of water. She could be from a far - off part of the ocean that Percy has never explored. Her appearance could bring new mysteries and adventures for Percy, as she might know secrets about the deep sea that are crucial to the safety of the demigod world.
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 Venator wizard who can manipulate time could be an interesting addition. He could help Percy in his quests by using his time - manipulation powers to gain an advantage. Another could be a half - Venator, half - demigod character who is conflicted about which world to side with.
A shape - shifting creature that can take on the form of any animal. It starts off as an enemy, trying to steal something important from Percy and the Wanderer, but later realizes they are on the same side and becomes an ally. This character could bring a lot of action and mystery to the fanfiction.
A centaur who has knowledge of ancient prophecies involving both Percy and Artemis could be added. The centaur could act as a guide or a mentor to them during their adventure. He could provide crucial information about the enemies they are facing and how to use their combined powers effectively. For example, he might know of a weakness in a powerful foe that only Percy's unique abilities and Artemis' lunar powers can exploit.
A young demigod who has the power to communicate with the spirits of the monsters. This character could help Percy understand the motives of the monsters better and maybe find non - violent solutions to some of the conflicts.
One potential character could be a wise old hermit who lives in a secluded part of the paradise. He could offer Percy valuable advice and knowledge about the secrets of the paradise.
You could have a character like Marie, a young demigod with the power to control the wind. She grew up in New Orleans and knows all the secret alleyways and hidden places in the city. Another could be Jacques, an old Cajun fisherman who is secretly a protector of a magical spring near the bayou and has some knowledge of the ancient Greek magic that Percy is familiar with. And then there's Lila, a voodoo priestess - in - training who teams up with Percy to fight against a common enemy.
A new demigod from a previously unheard - of god or goddess. Maybe a child of a minor deity who has some unique powers that could either help or hinder Percy in the situation of the collapse. For example, a child of Hypnos who can manipulate sleep and dreams, and their powers could be used to either give Percy visions of how to fix things or put him in a dangerous trance.
A new healer character could be added. This character could be both intrigued and a bit wary of Percy's blood - bending ability and could try to help him understand it better.
There could be a local guide in the place where Percy is exiled. This character could be an outcast from their own community and help Percy navigate the strange new land.