As I'm not aware of the actual 'oni and the great bird' story, it's difficult to say for sure. However, in general, in a story named like this, the oni, which is likely to be some sort of supernatural being, and the great bird are likely to be the central figures. There may also be characters related to the environment they are in, like people living in the area where the oni and the bird interact, or other magical creatures if it's a fantasy - style story.
I haven't heard about this 'oni and the great bird' story before. It would be great if you could give some more details like where you heard about it, or if there are any key elements in the story that you can remember. This would help me to better answer your question.
The main characters in the love bird story could be the two love birds themselves. They are likely to be the central focus, with their actions and relationship driving the story forward.
The main characters are clearly the king and the singing bird.
Mother bird Momo is the central character. Her chicks are likely to be key characters as well. There could also be other animals in the story like squirrels that live near Momo's nest. They might interact with Momo in some way, for example, the squirrels could give Momo a warning when a predator is approaching. However, Momo and her chicks are the most important characters in this kind of story.
The main character is obviously Momo, the mother bird. There might also be her chicks which are important characters as they are the ones Momo is taking care of.
Since I don't know the exact 'Black Bird Series Story', it could be that the main character is the black bird itself. It might be a solitary bird with a unique personality.
I don't know for sure as I haven't played or read it. But it could have a brave hero or heroine who is on a quest related to the stepping stones. There might also be an oni character that plays a major role, either as a friend or foe.
In 'the girl and the bird story', the primary characters are the girl and the bird. The girl could be of any age, from a young child to a teenager. She might be living in a particular place, like a small village or near a forest. The bird could be a specific type, such as a sparrow or a dove. Their personalities and the roles they play in the story will be crucial. The girl might be the one who initiates the contact with the bird, or the bird might be the one to approach the girl first. Their relationship will be developed as the story progresses.
As I don't know the exact 'bird boy story', I can only guess. The main character is probably the 'bird boy' himself. There might also be some other characters like his family members who might not understand his connection with the birds at first.
In the 'bird boy story', the main character is obviously the boy who has a relationship with the birds. There could also be other characters like his family members who might not understand his connection with the birds at first. And perhaps there are some villainous characters, like hunters who are a threat to the birds. The birds themselves, like a flock of sparrows or a solitary raven, could also be considered main characters as they interact with the boy and drive the story forward.