A young apprentice who wants to learn from the poison dragon slayer. This character can bring out the nurturing side of the slayer as they teach the apprentice about the dos and don'ts of slaying dragons and handling poisons.
A rival slayer who uses different methods and doesn't believe in the poison - based approach. This creates tension as they constantly compete with the poison dragon slayer, whether it's for the glory of slaying a dragon or for the limited resources related to dragon - slaying, like rare antidotes and weapons.
There could be a wise old mentor who was also a poison dragon slayer in the past. He can guide the main slayer with his years of experience and knowledge about different poisons and dragons.
A young dragon slayer - in - training who idolizes Natsu. This character could be from a far - off land and has heard tales of Natsu's dual powers. They could have their own unique magic related to a different element that complements Natsu's powers.
Often, they start off as strangers. The Poison Dragon Slayer might be confused by the Ninja way of life, like the use of hand signs for jutsu. Naruto, being the friendly and curious type, would approach the slayer and try to understand their powers. They gradually build a friendship based on mutual respect for each other's abilities.
There could be a young mage who idolizes Natsu and joins him on his adventures. This character could be inexperienced but full of enthusiasm, providing some comical moments as well as opportunities for Natsu to be a mentor.
Natsu could be a great ally. Since he is also a dragon slayer, he could offer advice and support to Lucy in her elemental dragon - slaying journey. Happy, Natsu's flying cat companion, could also be helpful in terms of providing transportation and some comic relief. Erza is another potential ally. Her strong combat skills and leadership could be valuable when Lucy faces tough dragon - slaying challenges.
The Magic Council could be potential enemies. Since Natsu is an outlaw, they would be the ones to try and capture him. Also, dark guilds might see him as a threat or a valuable asset to capture. They could send their strongest members after him.
Other dragon slayers could be her potential allies. They might recognize her skills despite her being a princess. Also, magical creatures who are enemies of the dragons, like phoenixes or griffins, could side with her. And some wise old wizards or witches who see her potential might offer their help.
One idea could be that the poison dragon slayer has to overcome a rare and powerful poison - based curse that is slowly sapping their strength. They must find a mythical antidote hidden in an ancient dragon's lair.
The Priestess is an obvious one. She has already shown admiration and a certain closeness to the Goblin Slayer in the original story. Then there could be a female knight who is impressed by his combat abilities against goblins. Also, an adventurer girl who is new to the goblin - slaying business and looks up to him as a mentor could be part of it.
Natsu could be one of her potential allies. Since he is a dragon slayer himself, he could understand some of the challenges Lucy faces as a Dark Dragon Slayer. He might offer his fire - based powers to complement Lucy's dark dragon slaying abilities. Another could be Erza. With her strong combat skills and leadership, she would be a great asset in battles against dark dragons. Erza could also protect Lucy when she is still learning to control her new powers.
One popular 'Harry Potter, Poison Dragon Slayer' fanfiction might be 'The Adventures of the Poison Dragon Slayer in the Wizarding World'. It often combines the elements of slaying the poison dragon within the rich backdrop of the Harry Potter universe, with new characters and exciting plot twists.