Deadshot's origin story is that he was a skilled marksman named Floyd Lawton. He came from a wealthy but troubled family. His father was abusive, which led to a lot of inner turmoil for Floyd. He grew up with a fascination for guns and shooting, and his skills became legendary. Eventually, he turned to a life of crime, using his marksmanship for hire, taking on assassination jobs and becoming one of the most feared hitmen in the DC Universe.
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.
In some of the best Deadshot stories, he is often pitted against other highly skilled assassins. His internal struggle between his job as a killer and his own sense of morality makes for a really interesting narrative. He has moments where he questions whether what he does is right or wrong, which adds depth to his character.
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.
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.
The story where Deadshot takes on a powerful crime syndicate all by himself is a great one. He uses his amazing shooting skills to take out the bad guys one by one, even when he's outnumbered. It's really exciting to see how he maneuvers through the dangerous situations.
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.