She could be a former pirate captain herself. Maybe she was one of the most feared pirates in her time, and her skills and reputation were passed down to Luffy in some way, even if he didn't know it was from his mother.
One common theme is self - discovery. When Natsu meets another version of himself, he often learns new things about his own capabilities and personality. Another theme is cooperation. Since they are essentially the same person, they have to learn to work together despite their initial differences.
In this fanfiction, it could be that Luffy's mother was thought to be dead but was actually held captive by a powerful enemy. When Luffy finally meets her, she's weak but still full of spirit. She encourages Luffy to keep fighting against the corrupt world of pirates and marines alike. She might also have some inside information about the One Piece, like a clue that she's been holding onto all these years, which sets Luffy on a new and exciting part of his adventure.
A possible plot could be that Spyro discovers a hidden message or prophecy that indicates his mother is alive. He sets out on an adventure, facing dangerous terrains and foes. Meanwhile, his mother might be trapped in a different dimension. Spyro has to find a way to break through to that dimension. When they meet, his mother could be a very powerful dragon. She could teach Spyro about their dragon heritage and how to better control his powers for the good of their kind.
The main antagonist might be a dark sorcerer. This sorcerer has put a spell on Spyro's mother long ago, trapping her. He doesn't want Spyro to find her because he fears that together they will be strong enough to break his power. He uses his minions to try and stop Spyro during his journey to find his mother.
In a 'naruto meets natsu fanfiction', they might start off as rivals. Naruto, with his ninja skills and determination, and Natsu, with his dragon - slayer strength. But as they get to know each other better, they realize they have a lot in common. For example, they both have a strong sense of loyalty to their friends. So they end up becoming good friends and combining their powers to protect their respective worlds from threats that could endanger both.
Well, it could be about Nashi going on an adventure with Natsu. Maybe they discover a new magic together and have to fight some bad guys to protect their world.
The main characters are obviously Nashi and Natsu. Nashi is likely a new and interesting character, while Natsu is a well - known and powerful wizard from the original series.
There's a great piece of 'natsu meets natsu dimension travel fanfiction' where Natsu travels to a parallel dimension and meets another version of himself. This other Natsu has different magical powers. They end up teaching each other new spells and techniques while trying to find a way to close the rift between their dimensions. It's really exciting to read how they interact and grow together.
Well, clearly Lucy and Natsu are the main characters. Lucy is often depicted as a smart and resourceful character, while Natsu is more of the impulsive and strong - willed one.