Sometimes it could be a powerful shinobi from another village. For example, if Naruto has done something that benefits their village as well during a joint mission or diplomatic encounter, they might reward him with something valuable like a scroll with secret techniques.
One example could be Naruto getting a special jutsu as a reward. Maybe after a particularly difficult mission, he is rewarded by an elder in the village with a powerful and unique jutsu that helps him in future battles.
Character interaction is a big characteristic. In 'Naruto' rewarded fanfiction, we often see characters from different villages interacting in new ways. For example, Naruto befriending a rogue ninja from a different land. Also, the themes can be different. While the original 'Naruto' has themes of friendship and perseverance, a fanfiction might focus more on the darker side of the ninja world, like the politics and power struggles among the villages.
In Naruto fanfiction, war rewards can vary greatly. One common reward could be powerful jutsu scrolls. For example, a character might be rewarded with a long - lost or forbidden jutsu scroll that gives them a new and unique ability.
Obviously, Naruto himself is the main character as he is the one sent back in time. Sasuke is also often involved as Naruto's relationship with him is a central part of the Naruto story. Kakashi could be involved too, as Naruto might seek his help or try to influence his training methods. Also, the various Hokages might be important characters as Naruto could interact with them in the past to change the course of events.
The main characters are often Naruto, as he is the focus of the mecha concept. Shikamaru could also be a main character in this type of fanfiction. He would be the strategist, trying to figure out how to best utilize the mecha Naruto in battles. Additionally, Orochimaru might be a character in some cases. He could be interested in stealing the technology of the mecha for his own evil purposes or trying to manipulate Naruto through it.
Sakura would be a likely candidate. As a skilled medical ninja, she has the knowledge and ability to diagnose the poison and attempt to create an antidote.
Maybe a rogue ninja group that wants to sell Naruto to the highest bidder. They see him as a valuable asset due to his strength and status in Konoha.
It could be Orochimaru. He's always interested in powerful artifacts, and the mask Naruto gets would be no exception. Orochimaru would likely try to steal the mask from Naruto to add to his collection of powerful items and use its power for his own dark experiments.
In 'naruto gets stabbed fanfiction', it might be a new enemy that has emerged, someone with a powerful and unknown jutsu. This enemy could see Naruto as a threat to their plans and decide to stab him to eliminate him. Or it could be a character who has been corrupted by dark power, like a former friend or ally who has fallen to the dark side and no longer recognizes Naruto as a friend.
Sakura could potentially be Naruto's girlfriend in some fanfictions. Although in the original series she had feelings for Sasuke for a long time, in fan - created stories, the writers might explore a different path where she realizes Naruto's true worth and they end up together.