First of all, Naruto's immortality would change the power dynamics in Fairy Tail. He could be a mentor figure to some of the younger wizards, teaching them about perseverance like he learned in his own world. The story might also involve Naruto exploring the different types of magic in Fairy Tail. His immortality could lead to him taking risks that normal characters wouldn't, which could result in him uncovering secrets about the world or the magic itself, and this would be the key to the continuous development of the storyline.
Well, in such a fanfiction, the storyline might develop with Naruto's immortality bringing new challenges to the Fairy Tail world. Maybe he has to deal with dark guilds in a different way because he can't be killed easily. His ninja skills could also blend with the magic in Fairy Tail, creating unique combat styles.
The development could start with Naruto being transported to the Fairy Tail universe. Since he's immortal, he might initially be seen as a strange and powerful being. As the story progresses, he could form alliances with Fairy Tail members. His immortality might make him a target for some villains who want to study or use his power for evil, and this could drive the plot forward with lots of action and drama.
Chapter 116, "Group Freeloading!", is the clearest early answer because it turns Director Sun's situation into a concrete plot event. A useful checkpoint is the way the scene starts with But before the audience in the live room had time to continue brewing...
Chapter 166, "Daniu Gets Jealous!", is the clearest early answer because it turns Zhao Lang's situation into a concrete plot event. The chapter turns that into something concrete by moving from Only after everyone in the small courtyard had left, did Zhao Lang...
Chapter 352, "Furong Cake", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. Early on, Finding Liu Suqing's address was not an easy task.. By the end, It was filled with various flowers and plants, fragrant and....
Chapter 148, "None are Normal", is the clearest early answer because it turns Du Qinglian's situation into a concrete plot event. The chapter turns that into something concrete by moving from Exiting the cottage, Director Sun picked up the phone.
Chapter 237, "Top of the Three Lists! Truly Deserved!", is the clearest early answer because it turns Zhao Lang's situation into a concrete plot event. Early on, It seemed as if, believing the spilled water couldn't be recollected,....
Chapter 445, "Mysterious Creature Appears!", is the clearest early answer because it turns Dean Yu's situation into a concrete plot event. Early on, Maybe I should just forget it, I can just watch you from below."....
Chapter 197, "Dear Brother", is the clearest early answer because it turns Su Yinwan's situation into a concrete plot event. Early on, Seeing that no one cared about what she said, Su Yinwan immediately.... By the end, Wen Jiaojiao, aren't you underestimating me?.
Chapter 270, "Heavenly God Jiang Yu Returns?!", is the clearest early answer because it pushes Jiang Mingyu into a new phase or setting.
Chapter 19, "I dare you to touch her!", is the clearest early answer because it turns Su Yinwan's situation into a concrete plot event.
Chapter 299, "Only Got Second Place in the Whole Grade", is the clearest early answer because it turns Lili's situation into a concrete plot event. The chapter gives readers a real answer by opening on She said as she poured Old Sir Jiang a cup of tea, "Dad, you might...