As I don't know the details of the 'hot dex story', I can't say who the main characters are. There could be a character named Dex who might be the central figure, but without more information, it's impossible to be certain.
If the 'hot dex story' is a mystery - type story, there could be a detective - like character named Dex as the main character, with other supporting characters like his sidekick or the people he is investigating. However, if it's a different genre, say a love story, then Dex could be one of the lovers, and there could be other characters such as their friends or family members involved in the story.
It depends on the nature of the dex stories. If it's a story about Dex in a school setting, there might be classmates, teachers, and a bully or two as main characters. For example, Dex could be a student who is trying to fit in while also dealing with a mean classmate. The teacher could be a guiding figure in Dex's life at school. If it's an adventure dex story, there could be a group of adventurers with Dex as the leader or a key member, and each member of the group would have their own unique personalities and skills that contribute to the story.
I'm not sure specifically what the 'hot dex story' is as the term is rather ambiguous. It could be a story related to a 'dex' which might refer to a Dexter or a Pokedex in some fictional context. Without more information, it's hard to say for sure.
The main characters are Fiona and Dex, of course. Fiona is likely to be a central figure in the story, with her own set of characteristics, dreams, and flaws. Dex is also important. He might be the male lead who has his own story arc that intertwines with Fiona's.
Hot dex stories might also be related to some sort of technological dex, like a device's database index. So it could be about how developers found and fixed bugs by exploring the dex of the software. There could be stories of finding security loopholes through examining the dex of a system's access control, which led to major improvements in security.
The main characters are Ash and the Dex Holders.
Since I don't know the details of 'the hot room story', I can't say for sure who the main characters are. It could be a family trapped in the hot room, so the main characters would be the family members.
Since we don't know the exact nature of 'the hot zone story', the main characters could be various types of people. If it's about a disaster - stricken hot zone, they might be rescue workers, local survivors, or government officials trying to manage the situation. For instance, if it's a story about a volcanic eruption making an area a hot zone, the main characters could be volcanologists studying the eruption, people trying to evacuate, and those providing relief to the affected.
As we have no information about the 'hot pulse story', it's impossible to determine the main characters. They could be scientists if it's a scientific - based story, or they could be ordinary people in a story about a natural phenomenon like a heat wave. In a fictional adventure story, they might be brave heroes or heroines.
Perhaps the main characters are the visitors to the hot spring. They could be tourists from all over the world, each with their own reasons for coming to the hot spring. Some might be there for the health benefits, some for the novelty, and others just to have a unique experience. It's also possible that there are local characters who are regulars at the hot spring and play important roles in the story, like an old man who has been coming to the hot spring for decades and shares his wisdom with the other visitors.
Often, there is a young and plucky protagonist. This character is new to the world of adventure but has a lot of heart and determination. They learn and grow throughout the story, facing challenges head - on and making friends and enemies along the way.