A common plot point is the false accusation. Naruto could be wrongly accused of stealing power or secrets in the DxD world. This would lead to his betrayal by those around him who believe the lies.
Another plot point could be a power struggle. There might be a character in the DxD universe who sees Naruto as a threat to their own power. So, they engineer a situation where Naruto is betrayed to get him out of the way. They might manipulate others into thinking Naruto is a danger.
Often, in these fanfics, Naruto discovers a conspiracy within Konoha. Maybe some hidden group within the village is trying to get rid of him because they see him as a threat to their power. So they manipulate events to make it look like Naruto has betrayed Konoha. As a result, Naruto is hunted by the very people he once protected. He then has to use his skills and wits to survive while also trying to clear his name.
One common plotline could be a character from Naruto being transported to the DxD world and feeling betrayed by the new characters they meet. For example, they might trust a devil at first but later find out they were being used for some dark purpose. Another plotline could involve a Naruto character's skills being exploited in the DxD world in a way that makes them feel betrayed by their own abilities. Maybe their power is harnessed in a way that goes against their moral code.
One possible scenario in such a fanfic could be that Naruto is betrayed by his new comrades in the DxD world. Maybe they misunderstand his motives or are jealous of his power. For example, they might think he's using his abilities for his own gain rather than the common good.
Often, there will be a plot point about how the pregnancy affects Naruto's ninja duties. Will he be able to continue being a ninja? Or will he have to step back? And there's also the question of how the village will react. Some might be accepting, while others could be very judgmental, creating a lot of conflict within the story. Plus, the mystery of how he got pregnant in the first place can be a major plot driver, like if it was a result of an experiment gone wrong or some ancient curse.
One common plot point could be the character with the demon arm struggling with its power. For example, they might have a hard time controlling it during battles, which could lead to some unexpected and dangerous situations. Another plot point could be the origin of the demon arm. Maybe it was a curse from an ancient evil or a result of some forbidden jutsu experiment. Also, the demon arm might attract other dark forces, creating more conflicts in the story as the character has to deal with not only the arm's power but also those who seek to use it for their own malicious purposes.
Power struggle is also a frequent theme. Naruto is a powerful ninja, and in the High School DxD world, power is highly coveted. His powers might attract the wrong kind of attention, and those who want to gain or maintain power could betray him to eliminate a potential rival.
One common plot point is Naruto struggling with the initial concept of the Rasenshuriken. He might have trouble getting the chakra control right at first.
One common plot point is Naruto facing an unbeatable foe. This enemy is often far stronger than any he has faced before, pushing him to his limits. Another is Naruto making selfless sacrifices. He might choose to give up his life to protect his friends or the village. Also, there could be a build - up of his relationships before his death, like his final conversations with Sasuke, Sakura, and others.
One common plot point is the revelation of Naruto's true parentage. Usually, there's a big moment where it's disclosed that Tobi is his father, which causes a stir in the ninja world. Another is Naruto inheriting some of Tobi's unique abilities or knowledge. For example, he might gain some special jutsu related to Tobi's powers.
He could be betrayed by a false friend in the DxD world who spreads lies about him. For instance, telling others that Naruto has a hidden agenda to take over their realm.