Since we don't know the exact 'boy with horns story', it's hard to say. But it's likely the boy with horns is the main character.
I'm not entirely sure which specific 'boy with horns story' you're referring to. It could be about a boy in a fictional or mythological context who has horns for some special reason, like being a demon - like character or having some sort of magical transformation that gives him horns.
The story might involve a fantasy world where the boy with horns has special powers or faces unique challenges.
Maybe it's a hybrid creature that has been created accidentally through some magical experiment gone wrong. It has wings, horns and hoofs and is trying to find its place in the world. It could be a really interesting main character as it would have to deal with not only the normal MLP problems but also the fact that it's different from everyone else. It could start out as an outcast but gradually earn the respect and friendship of the other characters. For example, it could use its unique abilities to save a group of ponies from a dangerous situation, which would make them see it in a new light.
The comic might revolve around the boy's struggle to fit in with society because of his unique poison horns. Or, it could be an adventure where he uses the horns to fight evil.
It might be a coming-of-age tale where the boy with red tipped horns learns to embrace his difference and use it to his advantage in a magical world filled with adventure and mystery.
It could be a fantasy tale where the boy with sheep horns has special powers and adventures in a magical world.
I'm not sure specifically who the main character is without more context. It could be a young man named something like Tom or Jack who embodies the 'golden boy' traits.
The main character is the boy who lives in the bubble.
Obviously, the boy is the main character as it's named the 'boy and fence story'.