Well, relationship building is a big theme. Naruto has to build a relationship with his fiancé, which can be full of challenges. There are also themes of loyalty and trust. He has to figure out if he can trust his partner and vice versa. In addition, some fanfictions explore the theme of sacrifice. Naruto might have to sacrifice some of his own desires or freedoms for the sake of the engagement. There could also be themes related to family, as the engagement may bring new family dynamics into play.
The theme of redemption is also quite common. Itachi has done a lot of bad things in the original story, and in these fanfictions, his relationship with Naruto can be a way of finding redemption. Naruto, on the other hand, is often portrayed as the one who can bring out the good in Itachi. Another common theme is the exploration of love that transcends boundaries, not just in terms of their opposing positions in the ninja world, but also in terms of their personalities and past experiences.
Definitely. A lot of these fanfictions play with the idea of how the ninja world would react to such an engagement. Naruto is seen as a hero in the series, and Itachi has a very complex reputation. So when they are engaged in fanfiction, it can lead to all sorts of interesting plotlines, like political unrest, or the formation of new alliances within the ninja villages.
One possible plot could be that Naruto, after achieving great things in his own village, travels for some reason to the world where Konoka lives. They meet by chance, and Naruto's heroic nature and kind heart immediately attract Konoka. As they spend more time together, they start to develop feelings for each other and eventually get engaged. Their engagement might face some opposition from people who don't understand their relationship, but they overcome it through their love and determination.
One possible supporting character could be Naruto's friends from Konoha. They might visit Naruto in Konoka's world and be a bit skeptical at first about his relationship with Konoka. Another could be Konoka's family members. Her father, for example, might be initially hesitant about Naruto but then come to accept him. There could also be some local villagers in Konoka's place who become friends with Naruto and help him adjust to the new environment.
One possible plot could be that their villages arrange their engagement as a way to strengthen the alliance between Konoha and Sunagakure. Naruto and Temari initially resist but then gradually fall in love as they get to know each other better.
Sakura would be really happy for them. She has seen Naruto grow and has always wanted him to find true love. Since she has moved on from her old feelings for Naruto, she would be supportive and might even offer to help with the wedding preparations. Shikamaru would probably be a bit lazy about it at first, but deep down he'd be glad for Naruto. He'd say something like 'What a drag, but if it makes you happy, Naruto.' Kiba would be excited, especially since Hinata is his teammate. He might tease Naruto a bit about finally getting the girl.
There's a fanfiction called 'Naruto's Unexpected Engagement'. It begins with Naruto getting engaged in a very unexpected situation. The story is full of twists and turns as he tries to navigate his new relationship. It also shows how his friends react to this new development in his life. Another one worth mentioning is 'The Engaged Ninja'. This fanfiction focuses on Naruto's growth as a person during his engagement, and how he uses his ninja skills not just in battles but also in dealing with relationship issues.
Well, it's possible. Fanfic writers have very creative minds. They might think it would be interesting to pair Naruto, a ninja from the Hidden Leaf Village, with Rias, a devil from the High School DxD universe. However, not all fanfics are easy to find. You may need to dig deep into the fanfic archives, using specific tags related to both Naruto and Rias on the fanfic platforms.
I've heard of 'Engaged to Female Itachi: Naruto's Journey'. This fanfic focuses a lot on Naruto's growth as a person within the relationship. He has to come to terms with his feelings for a version of Itachi that is female, and also deal with the reactions of his friends like Sasuke, who has his own complex relationship with the real Itachi.