Since I don't know the specific 'angel wing grooming fanfic', it's hard to say. But it could be the angel whose wings are being groomed, and perhaps a human or another angel who is doing the grooming.
There's no way to be certain without reading the actual 'angel wing grooming fanfic', but it's likely to include the angel whose wings are the focus of the grooming. There might also be a caretaker figure, which could be an angel with special skills in wing care or a human who has some sort of connection to the angel world and has been entrusted with this task. There could also be other supporting characters like other angels who observe or comment on the grooming process.
I'm not entirely sure specifically what this 'angel wing grooming fanfic' is about as it could vary greatly. It might be a fan - created story that involves the grooming or taking care of an angel's wings in a fictional, perhaps fantasy or supernatural setting.
The angel and the dragon are likely the central focus. However, in a Gundam Wing fanfiction, there might be engineers or commanders who are involved in the story. For example, an engineer who discovers something about the nature of the angel and the dragon that could change the course of events. And there could be a military commander who tries to use or stop the angel and the dragon depending on how they perceive their power and threat level.
Relena Peacecraft might also be one of the main characters in question. As she grows up in the fanfic, 'acting her age' could involve her becoming more politically astute and using her position to influence things for the better, which is a development befitting her age and status.
Typically, in Gundam Wing fanfic, the main characters would likely include Heero Yuy, Duo Maxwell, Trowa Barton, Quatre Raberba Winner, and Wufei Chang. But without reading the specific 'As I Touch the Sky' fanfic, it's hard to be certain if there are any new or modified versions of these characters.
Obviously, Connor and the angel are the main characters. Connor is the one experiencing homelessness, and the angel is the supernatural element that enters his life.
The main character is the angel, but there could be a mentor figure, perhaps an older and wiser angel who taught the main angel how to use the shotgun in the first place. And then there might be a character who represents the human world, a simple person whose life gets intertwined with the angel's mission. This person could be a source of inspiration for the angel to keep fighting with the shotgun.
Since I haven't read this specific fanfic, it's hard to tell. But it might include Naruto and some original characters related to the 'wingless angel' concept. Maybe there's a new character who is the wingless angel, and Naruto has some kind of interaction with them.
There could be a powerful devil king and a high - ranking angel as the main characters. The devil might be trying to spread chaos in the twilight realm while the angel is striving to maintain order. And there might be side characters who are affected by their actions, like the local inhabitants of this twilight world.
Obviously, Harry is one of the main characters since he's in the title. But without reading it, it's hard to say who else might be in it. There could be characters from the original source material that the fanfic is based on, like his friends or enemies. Maybe there are also new characters created specifically for this fanfic that interact with Harry in his role as the angel of death.
I'm not entirely sure as it depends on the specific fanfiction. But it might include characters from the original story that are given more depth or new roles. It could also introduce some original characters created by the fanfiction writer.