In a 'natsu half dragon fanfiction', you could set up a conflict where an evil dragon slayer wants to capture Natsu to use his half - dragon powers for his own evil deeds. Natsu has to fight not only against this slayer but also against his own inner dragon instincts that might be influenced by the slayer's dark magic.
One idea could be exploring Natsu's struggle to control his half - dragon powers. Maybe he accidentally causes destruction in the town and has to deal with the guilt and the fear of others. Another could be a story where Natsu discovers a hidden dragon clan related to his half - dragon heritage and has to prove himself to them.
Perhaps in the fanfiction, when Natsu turns into a dragon, he can communicate with other dragons in a way he couldn't before. This could lead to him uncovering secrets about his past and the origin of dragons in that fictional world. He might find out he has a special destiny related to the dragons.
In some fanfictions, Natsu might have different dragon slayer magic elements. Instead of just fire, he could have a combination of fire and lightning, which would make his attacks even more powerful and unique. Also, there could be stories where Natsu travels to different dimensions or time periods, which would introduce all kinds of new challenges and adventures for him. This could lead to him meeting alternate versions of his friends or even new characters.
In this fanfiction, perhaps Harry's connection to the dragon side would change his relationship with other magical creatures. He could have a special bond with dragons, understanding them on a deeper level. This could lead to him being involved in dragon conservation or training in a way that normal wizards aren't. Also, his appearance might be slightly altered, with some dragon - like features that make him stand out even more at Hogwarts.
One common theme is self - discovery. Since Natsu is a half - dragon, he often has to figure out what that means for him. He may discover new powers or abilities that come with his dragon heritage. Another theme is acceptance. He has to deal with how his friends and the guild will accept his new identity. For example, will they be afraid of him? Or will they see it as just another part of who he is? And power struggle is also a theme. Natsu may have to learn to control his new - found dragon powers, and there might be forces that want to either use him or stop him because of his half - dragon status.
Well, a cool plot might involve Natsu being transported to a parallel world where he is the only water dragon slayer. He has to adapt quickly to this new role and use his skills to fight against an evil force that is draining the water from that world. Also, he could meet alternate versions of his friends and have to convince them to trust him, since his powers are so different from what they know.
Another plot could involve Natsu turning into a dragon in a completely different world. He has to adapt to this new world as a dragon and find a way to turn back. Along the way, he meets other dragons who teach him about his new form and its capabilities. This could lead to him having a greater understanding of his own powers when he finally returns to his normal self.
One plot idea could be Hiccup's struggle to fully accept his half - dragon nature. He might face discrimination from both humans and dragons who don't understand his unique existence. Another could be his journey to discover his dragon heritage and the powers that come with it. Maybe he has to learn to control a special dragon - related ability that is a key part of his half - dragon identity.
One plot idea could be Hiccup's struggle to fit in both the human and dragon worlds. He might be shunned by humans for his dragon - like features and not fully accepted by dragons either because of his human side. Another idea is that he discovers a unique power that only he, as a half - dragon half - human, has. This power could be the key to saving both his human village and the dragon population from a common threat.
A great plot could be about Natsu and the ice dragon slayer (let's say a new character) teaming up to defeat a powerful dark wizard. They have to overcome their differences in magic types and personalities at first. Maybe the ice dragon slayer has a cold and reserved nature compared to Natsu's hot - headedness. As they fight together, they learn from each other and create new combined attacks. For example, Natsu could use his fire to heat up the air around the ice dragon slayer's ice attacks, making them more powerful and unpredictable.
Perhaps a plot where Natsu and Wendy are transported to a parallel world where their roles as dragon slayers are completely different. In this world, they are the only hope against an evil dragon that has enslaved all the other dragon slayers. They must quickly adapt to this new reality and use their sibling bond to figure out how to defeat the dragon.