In the fanfiction, their relationship would grow stronger. They would support each other more in battles. Lisanna could help Natsu control his dragon - slayer magic better, and Natsu would protect Lisanna with even more fierceness. They would also have some cute domestic moments like cooking together or just cuddling by the fireplace in the guild hall.
Their relationship could develop deeper. After the wedding, they would start to understand each other on a new level. Maybe Natsu would become more responsible towards Lisanna.
It could be a heart - warming story. The wedding might be a grand affair with all of Fairy Tail guild members present. Lisanna would look beautiful in a white dress, and Natsu, though a bit clumsy, would be full of joy. Their friends would surely pull some pranks during the wedding preparations, adding a touch of humor to the story.
Their relationship could develop through mutual respect for each other's strength. Natsu is a powerful wizard in Fairy Tail, and Kagura is no less in her own guild. When they first meet in battle or some other situation, they recognize the power in each other, which could be the start of a relationship where they gradually become friends.
At first, Natsu would probably be on guard around Irene. However, Irene's power and knowledge could be useful to Natsu in certain situations. As they spend more time together, Natsu's warm - hearted nature might start to thaw Irene's cold exterior. She could start to see him as more than just a Dragon Slayer and develop a soft spot for him. This could lead to a deepening friendship or a romantic relationship over time as they grow closer through shared experiences.
Their friends would likely be very excited. Lucy would probably be overjoyed and offer to help with things like baby clothes shopping. Gray might act a bit gruff on the outside but secretly be happy for them. Erza would be very protective, making sure that Lisanna has everything she needs and that the guild is a safe environment for the baby. Happy, Natsu's Exceed friend, would be constantly around, making cute comments about the baby and offering his own unique brand of support.
In some fanfictions, Natsu might save Lisanna from a powerful dark wizard. He could use his Fire Dragon Slayer magic to overpower the enemy and rescue her.
Their relationship could be developed uniquely by having Lisanna teach Natsu some of the more delicate magic she learned in Edolas. This would create a role - reversal situation where Natsu is the one learning from her. It would show a different side of their dynamic and deepen their connection as they spend time in this new kind of interaction.
One great fanfiction is 'Natsu and Lisanna's Adventure'. It beautifully portrays their relationship development. It starts with a simple quest they embark on together, and as they face challenges, their bond deepens. The author does a wonderful job of showing Natsu's protective side towards Lisanna and Lisanna's admiration for Natsu.
If in an alternate universe, Mystogan was raised in a different guild and Natsu was sent to bring him back to Fairy Tail. Natsu would initially be frustrated with Mystogan's aloofness. However, as they travel together, Natsu would learn about Mystogan's past and the reasons for his detachment. This understanding could lead to a friendship developing between them, and in the end, Mystogan might decide to join Fairy Tail because of Natsu's influence.
In many fanfictions, their relationship is often characterized by a deep loyalty. Natsu is always there to protect Lisanna, and Lisanna is a source of support for Natsu. For example, in some stories, when Natsu gets into a tough fight, Lisanna is the one who heals his wounds and gives him the motivation to keep going.
Their relationship often develops through shared experiences. For example, they might go on a quest together. During the quest, they face challenges and have to rely on each other. This builds trust between them. Natsu might start to see Lisanna in a new light, not just as an old friend but as someone he could have deeper feelings for. Lisanna, on the other hand, might become more confident around Natsu and show her true self more often.