Well, it could be that Marinette accidentally discovers Plagg while looking for something in Adrien's room. Plagg might initially be wary but then realizes Marinette's kind heart. They could team up to play a prank on Chat Noir.
When Plagg meets Marinette, it could be a significant moment for character development. Marinette could learn more about the kwamis from Plagg, which would give her a different perspective on the Miraculous she holds. Plagg might also start to see Marinette as more than just Adrien's friend. He could realize that she has her own strength and determination. This encounter could potentially change the dynamics between them and even affect how they interact with each other in future events related to the Miraculous.
In this fanfiction, the main characters are Plagg and Marinette. Plagg is an important figure in the Miraculous world. He is often associated with chaos but also has a soft spot for certain things like cheese. Marinette is a central character in the Miraculous Ladybug series. She has a double life as a normal girl and Ladybug. When these two meet, it creates a situation full of potential for interesting stories as their worlds collide.
She might be shocked at first. After all, she has no idea that Chat Noir has a kwami. But then she would probably be curious and start asking Plagg all kinds of questions.
In this fanfiction, Gabriel might be shocked to meet Plagg. Maybe he tries to take Plagg's power for his own purposes, like using it to enhance his control over the Miraculous.
It's hard to say which one is the sole main character. Gabriel has his own goals and plans which are central to the overall story of Miraculous. When he meets Plagg, his character development could take a new turn. On the other hand, Plagg is such a fun and unpredictable character. His reactions to Gabriel and how he might thwart Gabriel's plans could also make him a main focus. So in this fanfiction, they are both likely to share the role of main characters.
She might befriend Iron Man first. Since he's into technology and Marinette is quite creative when it comes to making things. They could bond over creating new gadgets or improving existing ones.
The plot might start with the hurt reader running away from home after an argument with their family. They end up in a magical garden where Tikki and Plagg are. Tikki offers the reader some magical treats that have the power to heal emotional wounds. Plagg, meanwhile, teaches the reader how to be more carefree. The reader then has a series of adventures with the kwamis, learning important life lessons along the way and eventually mending their relationship with their family.
It could be Hawk Moth. Since he's always after the Miraculouses, he might sense the presence of Tikki and Plagg with the hurt reader and try to manipulate the situation to get the Miraculouses. He could use the reader's vulnerability against them, trying to convince the reader that giving him the Miraculouses would solve all their problems.
It could be a cruel dog catcher. He's always on the lookout for stray dogs like Scamp. He sees Marinette trying to protect Scamp and tries to outwit her to catch Scamp. He doesn't care about the bond between Marinette and Scamp and is just focused on doing his job, which in this case, is seen as the 'bad' thing.