One possible storyline could be that Naruto is corrupted by a powerful dark force. This force twists his mind, making him see his friends and allies as threats, and he starts killing them one by one. Another could be in a post - apocalyptic Naruto world where resources are scarce, and Naruto has to kill to protect his own group from others who are desperate for food and water.
A storyline could involve Naruto being sent on a mission where he discovers that the people he thought were innocent were actually involved in a heinous plot against the Hidden Leaf. Feeling betrayed and in a fit of rage, he kills them. Another could be that an ancient curse is placed on Naruto that drives him mad with bloodlust, causing him to kill anyone in his path until he can break the curse.
In such a fanfiction, one possible storyline could be that Naruto is somehow mind - controlled and attacks Konohamaru without his own free will. Another could be a situation where there is a huge misunderstanding, like Konohamaru is framed for a serious crime against the village and Naruto, in his overzealous sense of justice, takes extreme action. However, this goes completely against the character development and the bond they have in the original series.
In such a fanfiction, one possible storyline could be that Sakura is under some dark magic or mind control which makes her turn against Naruto. Another could be a huge misunderstanding where she believes Naruto has done something unforgivable to her or their friends.
Perhaps there is a situation where Sakura is trying to protect Naruto from a dangerous attack, but due to some unforeseen circumstances, like a misdirected healing jutsu turning into a harmful one, she ends up killing him. It could then lead to a story of guilt, revenge, and the search for a way to bring Naruto back.
One possible plotline could be that Kushina is somehow mind - controlled or influenced by an evil force to harm Naruto. Maybe she's under a powerful genjutsu that makes her see Naruto as a threat to the village instead of her son.
One possible storyline could be Naruto being possessed by a Devilman - like entity. His friends then have to find a way to free him while dealing with the new, more dangerous Naruto. Another could be Naruto willingly accepting Devilman - like powers to defeat a greater threat, but then struggling to control them.
One possible storyline could be that Naruto is kidnapped by a rogue ninja group who wants to use his power for their own evil deeds. They might try to force him to reveal the secrets of his special jutsu. Another could be that he is kidnapped by a mysterious organization that believes he is the key to a long - lost prophecy. They hold him captive while they try to figure out how to use him to fulfill the prophecy. A third storyline could be that Naruto is kidnapped by a group of enemy ninjas from another village who see him as a threat to their plans for domination.
One consequence could be a shift in the power balance among the ninja villages. Since Orochimaru was a powerful and feared figure, his death might cause some chaos as his former allies or subordinates try to either avenge him or claim his resources. For example, some of his secret labs and experiments might be up for grabs, leading to potential conflicts.
One possible motive could be power. In some fanfics, Sasuke might be driven by an insatiable thirst for power and see Naruto as an obstacle. Another could be revenge, perhaps believing Naruto has wronged him in some way in that alternate story. Or it could be a matter of being corrupted by dark forces, which make him turn against Naruto.
Well, perhaps in the 'naruto abused by kushina fanfic', it could start with Kushina having a premonition of Naruto causing great harm in the future. So, in her attempt to prevent that, she goes overboard and starts abusing him. Or it could be due to some long - hidden family secret that makes her act out against Naruto, thinking she's doing the right thing for the family or the village in the long run.
In a fanfic, Tsunade's pregnancy might be a result of some sort of experimental medical jutsu gone wrong. Naruto could be the one to find a way to reverse it if she doesn't want the baby, or he could help her through the difficult pregnancy. He could also help protect her from those who might see her pregnancy as a weakness to exploit in the village.