In the world of comics, Batman has survived all encounters with Deadshot. Batman's skills and intelligence have allowed him to evade Deadshot's lethal attacks.
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.
Deadshot and Harley don't get together in the comics. Their characters are distinct and their storylines don't converge romantically. Each has their own complex dynamics and interactions with other characters.
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.
Batman would be a great character to include. His no - kill rule contrasts with Deadshot's assassin nature. Their interactions would be full of tension and moral debates. Harley Quinn could also be included. Her chaotic personality could add an element of unpredictability to the story. She might team up with Deadshot for a mission or be a distraction during one of his hits.