The unique feature is the blend of two different concepts. Naruto's world is based on ninjutsu and chakra, and when you add gunslinger elements, it creates a whole new dynamic. For example, the idea of a quick - draw gunfight combined with the speed and stealth of a ninja can lead to some really exciting action scenes.
There's a 'naruto gunslinger fanfiction' where Naruto discovers an ancient weapon that functions like a gun but is powered by chakra. This weapon changes the way he approaches battles and makes for some really cool fight scenes. Also, some fanfictions focus on how other ninja clans react to the introduction of gunslinger - like elements into the Naruto world. It often involves political intrigue as some see it as a threat to traditional ninja ways while others see it as a new opportunity for power.
Power - up themes are also common. For example, characters from one universe might gain abilities from the other. In some fanfictions, Naruto characters might get cybernetic enhancements, or Gunslinger Girls might learn ninjutsu. It makes for exciting storylines as it combines the unique powers of both worlds. Another common theme is the exploration of the moral gray areas. The Gunslinger Girl world has some ethical issues regarding the treatment of the girls, and when Naruto characters are introduced, they often question and try to change these aspects, leading to some really thought - provoking stories that are more than 100 words long.
First, give them a clear backstory. Maybe they were trained by an old gunslinger who had a connection to the supernatural world. This backstory can explain their skills and motivation. For example, if their mentor was killed by a devil, they would have a reason to be involved in the Highschool DxD world. Second, define their personality. Are they a lone wolf or do they like to work in a team? Their personality should be consistent throughout the fanfiction. Third, give them unique abilities related to their guns. It could be something like the ability to shoot bullets that can track their targets or bullets that can create barriers.
The information provided by the gunslinger TV series did not mention that the series had 40 episodes, nor did it mention that it could be watched for free. Therefore, I don't know if the gunslinger TV series has 40 episodes and if it's free to watch.