Maybe Natsu comes back with new powers. He might have to face old enemies that have grown stronger in his absence. Also, his relationships with his friends could have changed, and he'd have to work on rebuilding those bonds.
The plot of this novel could center around the great mage's return after 4000 years. When he comes back, he might find that the place he once knew is almost unrecognizable. His return could be a catalyst for many events. He may have to use his ancient magic to deal with modern - day problems. There could be a mystery about why he disappeared in the first place and what led to his return. He may also have to face the consequences of the passage of time, like the decay of old magic sites or the rise of new dark forces that he has to combat with his age - old wisdom and power.
I'm not sure specifically as I haven't read it in detail. But generally, it might be about a great mage coming back after a long period of 4000 years, perhaps to a world that has changed a great deal and facing new challenges, enemies or reuniting with old comrades.
A potential storyline could be that they discover a new island together. On this island, there are ancient secrets that only Nami's intelligence and Luffy's bravery can uncover. This adventure could bring them closer as they face challenges side by side.
In this fanfiction, perhaps Luffy and Nami's relationship could deepen. Luffy might become more protective of Nami after two years of growth. They could go on adventures together where Luffy's strength and Nami's navigation skills complement each other even more. Maybe there would be some tender moments between them during quiet times on the ship, like sharing stories of their two - year - apart experiences.
Well, from the title, it could be a story full of magic and adventure. The great mage returning after such a long time, 4000 years, might find the world completely different. There could be new magical systems, new races, and new threats. He or she might have to use their old - school magic skills to adapt to the new world and face the challenges that come their way.
Well, perhaps Percy comes back with new and amazing powers. He might be like a hero who has seen many things during those years away. He could use his powers to save his old friends from a big danger that they can't handle on their own.
Well, perhaps Percy comes back to find his old friends have changed a great deal. Maybe some have new powers or positions in their world. He could be faced with a new threat that only he can help to defeat because of his unique past experiences.
Well, from the title 'great mage returns after 4000 years light novel', it could be a story centered around a mage. After being away for 4000 years, he returns to a world that has likely changed a great deal. Maybe he has to relearn things, face new enemies or reconnect with old allies. It might also explore themes like the passage of time, power, and the mage's place in this new world.