Here's a more complex plot. There's a strange phenomenon causing Pokémon to lose their powers in a certain region. Torchic and Treecko, being the brave Pokémon they are, set out to find the cause. They meet various other Pokémon along the way, some of whom are also affected. They eventually discover that an evil scientist's experiment gone wrong is the root of the problem, and they have to work together with other Pokémon to stop it and restore peace to the region.
For Torchic, remember it's a Fire - type Pokémon, so it can be feisty and full of energy. It might be a bit impulsive at times, like charging into battles without fully thinking. Treecko, on the other hand, as a Grass - type, can be more calm and collected. It's likely to be more observant and patient, using its environment to its advantage in battles.
Well, it could start with Ash being in a new region where Treecko are very rare. He stumbles upon a young Treecko that is being bullied by other Pokémon. Ash steps in to protect it, and Treecko, seeing Ash's kindness, decides to join him. Their journey together focuses on exploring the unique ecosystems of this new region. Treecko has to adapt to new battle styles and opponents. Ash and Treecko also befriend a group of local Pokémon trainers who help them understand the secrets of the region. In the end, they face a powerful trainer who has a team full of strong Pokémon, and they have to use their combined skills and the knowledge they've gained to win the battle.
Some fanfictions focus on the relationship between Snivy and Treecko in a more emotional way. Maybe Snivy is feeling a bit lost and Treecko, being the more confident one, helps it find its purpose. It could be set in a time when there are changes in their ecosystem and they have to adapt together, relying on each other's strengths.
One possible plot could be that Torchic is a special, rare variant that has unique powers. Ash, with his determination, helps Torchic unlock these powers while they face off against powerful new villains in the Pokémon world. They could go on a journey to find a way to fully control these powers and in the process, make new friends and discover new Pokémon species.
The plot could involve Treecko being chosen for a special mission in the mystery dungeon. Maybe there is a powerful and ancient artifact hidden deep within the dungeon that has the power to change the balance of the Pokemon world. Treecko, despite being small and not as powerful as some other Pokemon, is selected because of its determination and pure heart. Throughout the story, Treecko has to overcome many obstacles, both physical and mental, to reach the artifact and decide what to do with it.
Well, there's a fanfic where Ash starts with Treecko called 'Treecko's Ascent with Ash'. In this one, Treecko is shown to have unique abilities that Ash helps to develop further. It also delves into how their partnership affects the other Pokémon in Ash's team. There may also be a fanfic that has a more comical take on Ash starting with Treecko, like 'Ash and Treecko's Hilarious Happenings', where they get into all sorts of funny situations during their travels.
There could be a fanfiction where Treecko evolves in an unexpected way while with Ash. For example, it might evolve during a battle against a powerful opponent, and this new form gives Ash an edge in his Pokemon journey. In this story, Ash and Treecko's bond also deepens as they face the difficulties together.
The relationship can develop through shared experiences. For example, if they face a tough battle together and have to rely on each other's skills to win. Ash could learn about Treecko's unique needs and habits, like what kind of food it prefers or the best environment for it to rest. This shows his care for Treecko.
A plot could be about your OC trying to infiltrate an enemy organization that is planning to take over the Kingsman agency. They have to go undercover and face many challenges along the way. Another idea is that your OC discovers a long - lost Kingsman technology that could change the balance of power in the world, and they have to protect it from falling into the wrong hands.
One idea could be exploring Apollyon's backstory before she became the feared warlord. Maybe she was once a young, idealistic warrior who was betrayed by her own people, which led her to her current ruthless ways. Another plot could involve Apollyon training a young apprentice who challenges her beliefs. A third idea is a story where Apollyon has to team up with her enemies to face a greater threat that endangers the entire For Honor world.