One possibility could be that it's a result of some powerful magic gone awry. Maybe during a spellcasting class or an encounter with a mysterious magical artifact. This new development might lead to him being ostracized at first as others are afraid or jealous. But then he could use his angel wings to his advantage, like flying faster and more stealthily than on a broomstick.
It could be a manifestation of his inner goodness. Harry has always been a heroic character. The angel wings might symbolize his pure heart and his unwavering determination to fight against evil. He might use the wings to rescue people in danger more easily, swooping down from the sky to save them from dark wizards or dangerous magical creatures.
Perhaps it's a gift from a benevolent magical being. An angelic figure from the wizarding world or a spirit that has taken a liking to Harry. This would give him a new sense of purpose. He could then use his wings to explore parts of the wizarding world that are difficult to reach, like hidden valleys or ancient towers where new magical secrets might be hidden.
Perhaps the wings grow as a result of some ancient magic that has been awakened within Harry. He could be exploring an old, forgotten part of Hogwarts and accidentally triggers a spell or a curse that gives him wings. At first, he might be scared and try to hide them, but as he learns to control them, he realizes they can be used for good, like helping him rescue trapped students or animals in the Forbidden Forest.
There could be many amateur authors out there who might write such a fanfiction. It could be a young, creative Harry Potter fan who loves to imagine new and exciting adventures for the characters. They might be inspired by their love for the series and the idea of giving Harry a new and unique ability like growing wings.
Hermione would probably be both curious and concerned. She'd want to research immediately to find out how and why this happened. Ron, on the other hand, might be a bit more in awe at first. He'd likely make some jokes about Harry looking like a strange bird, but still be supportive.
There could be a magical creature that takes on a human - like form and has black angel wings. This creature could be a guardian of some sort, maybe of an important magical artifact. It might initially be seen as a threat but is actually there to protect the wizarding world. When Harry discovers this creature, they form an unlikely bond, and the black angel wings become a symbol of their unique relationship.
Maybe Harry is exploring an ancient and forgotten part of Hogwarts when he stumbles upon a magical artifact that causes him to build a cocoon. Once he grows wings from this cocoon, he finds that he has a connection to a long - lost race of magical beings with wings. He embarks on a journey to discover more about this race, all while trying to keep his new form a secret from his friends at Hogwarts who might be afraid of his transformation.
In the fanfiction, Percy growing wings could be a sign of a new power awakening within him. This new power could be related to his godly heritage. He could use the wings to travel to new and mysterious places, face new enemies, and also discover more about his own identity. The wings could also symbolize his growth and evolution as a character, taking him on a journey of self - discovery that is both exciting and dangerous.
I'm not sure of a specific 'Harry Potter' fanfiction just about angel wings off the top of my head. But you can start by looking on popular fanfiction websites like Fanfiction.net or Archive of Our Own. You can search for the tags 'Harry Potter' and 'angel wings' and browse through the results. There are likely to be some creative and interesting stories there.
The 'angel' could be a new character created by the fanfiction author. This character might have some extraordinary powers or a very kind heart that earns them the title of 'angel'. It could also be an existing character who is portrayed in a new light, like Luna Lovegood. Luna has this ethereal quality about her already, and in this fanfiction, she could be elevated to an 'angel' - like status, perhaps being the one who always saves the day with her unique insights.
Hermione would probably be very curious at first. She'd immediately start looking through all her books to find any information about such a strange transformation. Ron, on the other hand, might be a bit more freaked out. He'd probably make some jokes at first to cover up his unease, but then he'd be there to support Harry. Ginny would likely be concerned but also find it kind of cool and would try to help Harry get used to his new wings.
Hermione could be a main character. She would be the one trying to figure out the magical theory behind Harry's cocoon - building and wing - growing. She might be researching in the library, looking for any mentions of similar phenomena in ancient magical texts.