Yes, in some fanfictions, Naruto is depicted as the heir of the Namikaze clan. This often gives a new twist to the story, as it ties him more closely to his father's heritage and can lead to new plot developments, like exploring more about the clan's secrets and abilities.
One interesting story could be about a young Namikaze clan member discovering a long - lost jutsu. This jutsu might give them an edge in battles and also help them understand their clan's history better.
Naruto Uzumaki, even though he's not strictly a Namikaze in the beginning of the story, is also a popular character in Namikaze clan fanfiction. Since he's Minato's son, a lot of fanfictions explore his connection to the clan. They might write about how he discovers more about his father's clan and how he uses their techniques and heritage to become even stronger.
The implications are numerous. He could be given the responsibility of restoring the Namikaze clan to its former glory. This might involve recruiting new members or reviving lost traditions. In terms of his relationships, he may have to deal with those who envy his new position or those who want to use him for their own gain. Moreover, his identity as the heir could attract the attention of enemies who see the Namikaze clan as a threat, leading to new conflicts and challenges for Naruto to overcome.
One possible motive could be revenge. Maybe Naruto was led to believe that the Namikaze clan was responsible for something terrible that happened to him or someone he cared about. Another motive could be power. If there was some sort of power within the clan that Naruto thought he could gain by eliminating them.
Well, perhaps the story could revolve around the Namikaze Clan Head having to deal with internal disputes within the clan. Some members might want to modernize the clan's ways while others are more traditional. Meanwhile, he has to protect the clan from outside threats, like rogue ninjas who target the Namikaze for their special abilities. He could also form alliances with other clans for the greater good of the village.
It's likely that this fanfiction is centered around the idea of resurrecting the Namikaze clan. Naruto, being the main character, would probably be at the forefront of this restoration. The story could show how he overcomes various obstacles such as lack of knowledge about the clan's past, resistance from within the Hidden Leaf Village who fear a powerful clan's resurgence, and his own personal struggles in taking on such a huge responsibility.
Yes, it is a very dark twist. In the original Naruto story, Naruto is a part of the Uzumaki clan, and the Namikaze clan is his father's clan. Having Naruto kill the Namikaze clan goes completely against the established relationships and values in the original series. It's a concept that challenges the idea of family and loyalty that is so central to the Naruto universe.
One interesting concept could be unique doujutsu abilities specific to the Namikaze clan. Maybe they have a doujutsu that can manipulate wind in extraordinary ways, like creating invisible wind blades or being able to sense the movement of air currents for better combat awareness. Another concept might be the origin of these doujutsu within the clan's history, perhaps related to some ancient pact or power.
Obviously, the Namikaze Clan Head would be a main character. His family members, like his wife and children if he has any, could also be important characters. And Naruto himself, since he is related to the Namikaze clan, could play a significant role, either as an ally or someone who challenges the clan head's decisions in some way.