There could be an adventure where the guild master has to deal with a rival guild that is causing trouble for Fairy Tail. They would need to use their leadership skills to strategize and protect the guild. This might include things like negotiating treaties or engaging in magical battles to defend the guild's honor. It would be full of drama and action, with the guild master at the center of it all.
The guild master could embark on a quest to find ancient and powerful magic artifacts. For example, they might search for a lost crystal that has the power to enhance the magic of all guild members. This would involve traveling to dangerous and mysterious places, like a forgotten underground temple filled with traps.
A plot could be about a new guild master having to deal with a powerful dark guild threat. The new guild master, say someone like a new character introduced in the fanfiction, has to unite the Fairy Tail members, who are initially skeptical of their leadership. They have to come up with new strategies to combat the dark guild's unique magic and overcome internal differences within Fairy Tail.
They could go on a quest to find a lost magical crystal. Naruto's tracking skills as a ninja and Sayla's knowledge of the Fairy Tail world's magic locations would be useful. Along the way, they might encounter various magical creatures and have to fight them using Naruto's jutsu and Sayla's magic.
A powerful dark wizard who was once a member of Fairy Tail but was banished for using forbidden magic could be a great antagonist. They hold a grudge against the guild and especially the guild master for their expulsion and now seek revenge by trying to destroy the guild from within.
Well, Naruto could bring his unique sense of justice to Fairy Tail. Since he has always been about protecting his friends and village, he would likely jump into any situation in Fairy Tail where the guild or its members are in danger. His Rasengan could be a very powerful attack against the various foes in the Fairy Tail world. And he could learn some magic from the Fairy Tail wizards too, like how to control magical elements which would be a whole new experience for him.
In my opinion, Makarov could be the ideal Fairy Tail guild master in game fanfiction. He has great leadership skills and a strong sense of justice. His magic power is also quite formidable, which can add a lot of exciting elements to the game.
One possible interesting plot could be Naruto, as the guild master, having to deal with a powerful dark guild that is threatening the safety of Fairy Tail. He could use his ninja skills and leadership to gather the members and come up with a unique battle strategy.
Naruto would likely change the guild's training regime. He'd focus on building physical strength as well as magical power. Since he's used to intense training himself, he'd push the members to be better. He might also introduce a system where members help each other more directly, like his team - based approach in Naruto.
Another great choice could be Laxus. He has that tough - guy exterior but also a lot of room for character growth. In a fanfiction as guild master, he could bring a different leadership style, more aggressive perhaps. He might change some of the guild's traditions while still maintaining the core values of Fairy Tail. He also has a great relationship with his team, which could be further developed in the fanfiction.
Perhaps they go on an adventure to find a healer who can ensure a healthy pregnancy. Along the way, they face various challenges like traversing through dangerous terrains. Jellal uses his magic to protect Erza and the unborn child, while Erza uses her combat skills when necessary. This adventure could also strengthen their bond with their guildmates as they all work together towards this important goal.
One possibility could be that Natsu is under some sort of dark magic influence. Maybe a powerful enemy has managed to control his mind, making him turn against the guild master. Another reason could be a misunderstanding. If some false information is fed to Natsu about the guild master being a threat to the guild or his friends, his hot - headed nature might lead him to take drastic action without fully understanding the situation.