A new transfer student who has some connection to the after - effects of the war could be introduced. Maybe this student is from a family affected by the war and has some knowledge of the spiritual world that Ichigo was involved in. They could become friends or rivals to Ichigo.
There could be new demigods. Maybe some who were hidden during the giant war and now come out. For example, a demigod of a less - known god or goddess.
Perhaps in this fanfiction, Ichigo returns to school but is constantly on edge, expecting another threat. So he starts to train secretly on school grounds, using his after - school hours to keep his skills sharp. This could lead to some misunderstandings among his classmates who might think he's acting strange or getting into trouble. He also might have to hide his injuries from the war, if any, from his teachers and friends.
There could be a new scientist who helps Peter with his web - shooter technology. Maybe this scientist has some secret knowledge about the symbiote or other aspects of Spider - Man's powers. Another new character could be a foreign exchange student at Peter's school who turns out to have some sort of superpower or connection to the superhero world. Or it could be a new villain's henchman who later has a change of heart and helps Peter.
As far as I know, there's no official mention of new characters in the Valkyries after story. But it's possible that some minor characters could be introduced to show the aftermath in the Valkyries' realm.
A street urchin who befriends Scrooge after his transformation. This urchin could represent the hope and innocence that Scrooge starts to cherish. The urchin could teach Scrooge about the simple joys of life that he has long forgotten.
A scientist from a rival organization who initially tries to undermine the Ghostbusters but later realizes they need to work together. This character could bring in new types of technology that the Ghostbusters have never seen before.
There could be a new professor at Hogwarts. Maybe a young and brilliant wizard who has just returned from a long journey in a far - away magical land. This professor could bring in new ideas and spells, and become an important figure in Harry's new path.
A young mermaid named Coral could be introduced. She has a special ability to communicate with sea creatures that even Peter doesn't know about. Another could be a mysterious old wizard who lives on the outskirts of Neverland and has knowledge of ancient spells that could help or harm Peter and his friends.
There could be young ninjas who look up to Sasuke. They might be orphans of the war, and Sasuke takes them under his wing. These new characters would bring fresh energy and new storylines as Sasuke mentors them.
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.