Well, it could be about a trainer who discovers a hidden entrance to the Hall of Origin. There, they meet legendary Pokemon and learn ancient secrets of Pokemon creation.
Maybe it's a story where a group of researchers try to unlock the mysteries of the Pokemon Hall of Origin. They face many challenges and dangerous Pokemon along the way. In the end, they might find out something that changes the understanding of Pokemon in their world.
One possible plot could be that a young Pokemon trainer has a strange dream about the Hall of Origin. This dream leads them on a journey to find it. As they get closer, they start to experience strange phenomena. When they finally reach the Hall of Origin, they are chosen by a legendary Pokemon to carry out an important mission, like protecting the balance between different Pokemon species in the world.
It could be about a human who discovers a hidden entrance to the Pokemon Hall of Origin. This human might have a special bond with a particular Pokemon that leads them there. Maybe they are on a quest to learn the secrets of Pokemon creation or to find a way to stop an evil force that threatens the balance in the Pokemon world.
It might be that the fanfic focuses on a trainer who discovers Necrozma's link to the Hall of Origin. This trainer could be trying to stop Necrozma if it's causing chaos, or perhaps they're trying to help it. They would have to navigate the mysteries of the Hall of Origin, which could be filled with ancient Pokemon knowledge and power sources. There could be other Pokemon guardians in the Hall of Origin that the trainer has to face or befriend while dealing with Necrozma.
It could be about Melmetal's origin story within the Hall of Origin. Maybe it discovers a hidden power there or meets other rare Pokemon.
It could be an experienced Pokemon trainer who has already conquered many gyms and is now seeking a greater challenge in the Hall of Origin.
One possible plot could be that a young trainer discovers a hidden entrance to the Hall of Origins and encounters Missingno there. The trainer then tries to figure out what Missingno is and how it relates to the other Pokemon in the Hall.
A young and curious trainer who has always been interested in the legends of Pokemon could be the main character. They might have heard rumors about the Hall of Origin and set out to find it.
Obviously, Melmetal could be one of the main characters. Another could be a trainer with a special connection to Melmetal.
There might be some legendary Pokemon that are guardians of the Hall of Origin. For instance, Arceus could be a key character, as it has a strong connection to the Hall of Origin. And then there could be other trainers who are either rivals or allies of the main trainer in the story. They could all have different motives regarding Necrozma and the Hall of Origin. Some might want to capture Necrozma for its power, while others want to protect it or the Hall of Origin from harm.
Well, in a fanfic about the Pokemon Hall of Origin and Ultra Beasts, you can expect a wild adventure. The Hall of Origin is a very mysterious place in the Pokemon world. Ultra Beasts are strange and powerful creatures from another dimension. A fanfic might explore how a trainer gets involved with the Ultra Beasts near the Hall of Origin. Maybe they accidentally open a portal to the Ultra Beast's world while exploring the Hall. It could also show battles between the trainer's Pokemon and the Ultra Beasts, with unique strategies based on the Ultra Beasts' strange abilities.
There could be battles between trainers trying to prove themselves against the legendary Pokémon. Maybe a young trainer stumbles into the hall by accident and has to find their way out while avoiding the wrath of the powerful legendaries.