Well, James' sad story is tied to his family. His family had high expectations for him which he couldn't meet. They were more interested in their own status and wealth. James wanted a different life, one full of adventure and freedom. In Team Rocket, he hoped to find a place where he could be himself, but things didn't go as planned. He and his partners often mess up their missions, and he has to endure Jessie's temper as well. All these make his story quite sad.
Well, it could be about a Pokemon that gets separated from its trainer. Maybe the trainer had to release it for some reason, like not being able to afford to keep it. The Pokemon then has to fend for itself in the wild, which is really sad.
Well, Cubone's sad tale begins with the loss of its mother. Cubone is often seen as a very lonely Pokemon. It wears the skull of its mother, which is a constant reminder of her absence. The skull also serves as a form of protection for Cubone. It wanders around, perhaps longing for the presence of its mother, and this sense of loss is what makes its story so sad.
Mewtwo was created in a lab through cruel genetic experiments. It was made as a clone of Mew but was constantly treated as a tool. It was isolated and experimented on, which made it feel a great deal of pain and loneliness. It had to struggle to understand its own existence and purpose in a world that seemed to only want to use it for power.
There was a Pikachu. Its trainer was really into winning battles. One day, Pikachu got seriously injured in a battle but the trainer still forced it to keep fighting. Eventually, Pikachu lost its ability to use its most powerful electric attacks. The trainer then decided to replace Pikachu with a stronger Pokemon. Pikachu was left at a Pokemon center, feeling abandoned and sad as it watched its old trainer leave with a new Pokemon.
One possible main character could be a Pikachu that lost its trainer in a storm. The Pikachu then has to search for the trainer all alone, facing all kinds of dangers in the process.
Mewtwo's story is sad because it was created through unethical means in a lab. It was isolated from the start, had no real family or friends, and was constantly being experimented on. All these things made it a very lonely and tormented being.
A Charmander's trainer lost interest in it after catching a stronger Pokémon. The trainer left Charmander in an old, abandoned building. Charmander was confused and sad. It didn't understand why it was left behind. It tried to find its way back to the trainer but got lost in the big city. There were so many things it didn't know about the human world, and it was constantly in danger from cars and other humans who were scared of it.
Once there was a Charmander. It was waiting for its trainer who never came back. It stayed by the Pokeball it was first caught with, hoping every day. As time passed, it grew weaker without proper care. Other Pokémon started to bully it because it was alone and sad. It was a truly heart - breaking sight to see such a once - lively Charmander in such a pitiful state.
One sad Pokemon story could be about a trainer abandoning their Pokemon. For example, a trainer might leave their old and weak Pokemon in the wild because it couldn't keep up in battles anymore. The Pokemon would be left alone, confused and sad, having known only the company of the trainer before.