Well, it could be that Naruto is exposed to a powerful and corrupting force. This force warps his sense of justice. Deadshot's character represents a more morally gray area compared to Naruto's traditional view of right and wrong. Maybe Naruto has a series of traumatic experiences that make him question his own values. He then sees Deadshot as a model of someone who can get things done regardless of the cost, and thus begins to transform into someone like Deadshot.
He would definitely gain Deadshot's incredible marksmanship skills. Naruto, who was already good at aiming his Rasengan and other attacks, would now be able to use firearms with extreme precision. His new ability might also include Deadshot's stealth skills. Naruto, who was used to sneaking around in his ninja world, would now be able to blend into the shadows even better in a more urban and modern setting like Deadshot's world.
First, you need to understand both characters well. Naruto is known for his determination and belief in friendship, while Deadshot is a skilled assassin. Then, come up with an interesting premise for their meeting, like a shared mission or a wrong - place - wrong - time situation. Keep the dialogue in character. For example, Naruto would likely be more talkative and try to persuade Deadshot towards a more positive path, while Deadshot would be more focused on the job at hand. Also, don't forget to add some action scenes that play to their strengths. Naruto's ninjutsu and Deadshot's marksmanship can make for some exciting battles in the fanfiction.
I also recommend 'Naruto and Deadshot: The Contract'. Here, Deadshot is hired to take out Naruto but instead, they end up forming an uneasy partnership. The author does a great job of exploring both characters' backstories and how they can find common ground despite their differences.
Naruto might become more serious. Deadshot is a very serious and focused character. So Naruto could lose some of his goofy and carefree nature and become more calculating in his actions.
Well, it could be that Naruto, in this fanfic, discovers Deadshot's skills and becomes a huge admirer. Maybe he starts to train in a similar way, focusing more on long - range attacks with kunai and shuriken, emulating Deadshot's precision.
One common theme is the clash of two different worlds. Bella is often from a more 'normal' world while Deadshot is a part of the dangerous and violent world of assassins. Their interaction and how they bridge this gap is a frequently explored theme.
One possibility could be that Naruto is drawn to boxing because of its physicality and the determination it requires. He might see it as a new way to test his strength and endurance outside of ninja battles. Maybe he starts training with a local boxing coach who sees his potential and helps him develop his skills.