Well, it could be about Naruto coming back and dealing with the PTSD of war. Maybe he has trouble adjusting to normal life again, like struggling to connect with his friends and family who don't fully understand what he's been through.
Well, one possibility could be that Naruto comes back with a new sense of purpose. Maybe he's determined to reform the ninja world based on what he's seen in the war. He could start by trying to improve relations between different villages.
It could be a rogue ninja who took advantage of the chaos during the war. This ninja might have been gathering power in the shadows and now sees Naruto as a threat to his plans.
Sakura could be a main character. She might be the one who helps Naruto deal with his emotional and physical wounds after the war. She could also be struggling with her own feelings towards Naruto now that he's back.
Well, a Ben return from war fanfiction can be really interesting. It might explore his post - war trauma, how he readjusts to civilian life. Maybe he has trouble sleeping or is jumpy at loud noises. The fanfiction could also show his relationships with family and friends changing. They might not fully understand what he's been through.
One possible plot could be Ben trying to reconnect with his old life but finding it difficult. His friends have moved on in different ways and he feels like an outsider. Another plot could be him having flashbacks during normal activities, like when he's at a crowded market or a noisy party.
In the 'Ash Return from War for Serna Fanfiction', it could be that Ash returns not just as a hero on the surface but is actually a bit of an anti - hero. He might have made some morally ambiguous decisions during the war. When he comes back to Serna, his actions and decisions start to divide the community. Some see him as a savior still, while others are wary of his new - found ways and the secrets he might be hiding.
Perhaps in the fanfiction, Ben returns but he's a changed person. He has seen the horrors of the space war and now he struggles to adapt to his old life. He might also have some new allies from the space war who come with him to Earth.
Another theme is growth. After going through the war, Steven is no longer the same innocent boy. Fanfictions usually explore how he has matured, both in his understanding of the Gem world and his place in it, as well as in his relationships with others. He might become more assertive or more empathetic.
Maybe Steven comes back with new powers. He could have learned some unique combat skills during the Grem war. For example, he might be able to control a new type of energy that he discovered while fighting the Grem.