Another character could be a villain who is hunting down any remaining Targaryens. He sees the orphan boy as a potential threat because he might grow up to claim power. This villain adds conflict and danger to the story, forcing the orphan boy and his newfound friends to constantly be on the run and develop strategies to outwit him.
The plot could revolve around the orphan boy's discovery of his Targaryen heritage. Maybe he finds an old relic or meets someone who tells him he has Targaryen blood. This could lead him on a journey to claim his rightful place in the world of the Targaryens.
The story might focus on the boy's struggle for acceptance and finding his place within the powerful Targaryen family. There could also be elements of magic and mystery involved.
Obviously, the orphan boy is the central character. Additionally, there might be a strict but fair orphanage caretaker. And there could be a wealthy benefactor who takes an interest in the boy's future and tries to help him in different ways.
Not having read 'the orphan boy story', it's hard to say for sure. However, the orphan boy himself is the central character. There could be other orphans in the story who become his friends or rivals. There may also be an adult figure, like a teacher or a priest, who plays an important role in the boy's life, either by guiding him or by providing some form of support or challenge.
It's possible that some of the more traditional and strict gods could be antagonists. They might view Aphrodite's act of adopting a mortal boy as going against the natural order. These gods could try to separate the boy from Aphrodite, either by tricking the boy or by putting pressure on Aphrodite. There could also be a dark force or a cursed entity in the story that targets the boy because of his connection to Aphrodite, seeing him as a way to get back at the goddess of love.
There could be a dark god or goddess, perhaps from the underworld, who sees Aphrodite's adoption of the boy as a disruption to the natural order. This deity might believe that mortals should suffer and that Aphrodite is interfering too much. So, they send their minions to kidnap the boy or try to corrupt his soul, so that Aphrodite would lose her beloved adopted son and be in despair.
Since we don't know the details of 'the dream of an orphan boy story', it's difficult to name all the main characters. However, the orphan boy is the obvious main character. There could be an antagonist as well, perhaps someone who tries to stop the boy from achieving his dream. It could be a bully in the orphanage or someone in the outside world who discriminates against him because he is an orphan. There might also be a mentor - like an old man who gives the boy advice and helps him on his path.
Obviously Jerry is one of the main characters since it's his story. There might also be other orphans in the orphanage who play important roles, like his best friend there.
In this fanfic, Aphrodite could adopt the boy for various reasons. It could be that she's lonely and wants a companion. The boy's journey would be interesting. He might struggle to fit into the new world with a goddess as his mother. There could be conflicts, like other gods being jealous or suspicious of the boy. But Aphrodite would be there to guide him. She could give him gifts, like the ability to charm people, which he could use for good, and in the end, he might become a great advocate for love and kindness just like Aphrodite.
The plot could involve Aphrodite seeing the little orphan boy in a desolate place, perhaps a war - torn area or a poor village. She takes pity on him and decides to adopt him. She then uses her powers to give him a new life, maybe endowing him with some special abilities or just protecting him from all the evils of the world.