Since I haven't read it, I can't say for sure. But it could be a human who has an interest in monster girls and maybe some of the more prominent monster girl characters.
The main characters in Monster Girl Gazer short story could include a young man or woman who is curious about the world of monster girls. There might be a group of monster girls with distinct personalities. For example, one could be a shy and gentle monster girl, while another might be more fierce and independent. And there could be an older character, perhaps a mentor - type, who gives advice to the main character on how to deal with these strange and wonderful creatures.
I'm not entirely sure as I haven't read this specific short story in detail. But generally, it might involve some unique encounters with monster girls, perhaps their relationships with humans or their own kind, and the events that unfold in the world they inhabit.
The main character, of course, is often a popular choice. He is the one who has the ability to 'gaze' at the monster girls. Also, the powerful and mysterious dragon - type monster girl can be really interesting to include. Her strength and unique abilities can add a lot of drama to the story.
I'm not sure exactly who the main characters are in 'Monster Girl Story' without more information. But it's likely to have a human character as a protagonist who serves as the link between the human world and the world of monster girls.
A plot could revolve around a monster girl gazer who accidentally gets a special power that allows him to understand the languages of all monster girls. This leads to him becoming a mediator between different monster girl tribes that are at war. He uses his newfound ability to broker peace and in the process, falls in love with a particular monster girl from one of the tribes.
Obviously, the hellhound monster girl herself is a main character. There might also be a sidekick or a friend who helps her through her adventures. Maybe a wizard or a brave knight who doesn't judge her for what she is.
The hellhound monster girl is the central figure, no doubt. But in addition to her, there could be a whole cast of characters. There may be a human character who initially fears her but then comes to understand and support her. There could be an ancient demon or spirit that has some connection to her origin or powers. And then there are the potential sidekick characters, maybe some smaller or less powerful monsters that follow her around, either out of loyalty or because they see her as a means to protect themselves in a dangerous world.
The main character is a male protagonist. And of course, there are various monster girls which can be considered as main characters in their own right as they play significant roles in the story.
Most likely the monster girls themselves are the main characters. Each with their own distinct features and personalities.
As not much is known about it, it's difficult to say. But it's likely the monster girl would be one of the main characters. There could also be other characters like local villagers or creatures from the alp area.
The girl and the alp - monster are likely the main characters. The girl could be a normal human girl from a village or a town in a fictional setting. She might be curious, brave or both. The alp - monster, on the other hand, could have its own motives and personality. It could be a mischievous alp, always playing tricks, or a more menacing one. And depending on how the story is crafted, there could be other characters that interact with them, such as a wise old hermit who gives the girl advice on dealing with the alp - monster, or a group of hunters who are after the alp - monster for some reason.