Well, they might start off by fighting each other. Deadpool with his unpredictable and crazy fighting style and Deathstroke with his highly trained combat skills. It could be a really intense battle.
It's hard to say. Deadpool has his regenerative power which gives him an edge in a long - drawn fight. He can keep coming back no matter how much damage he takes.
Deathstroke's age in the comics is a bit fluid. It often depends on the creative direction of the story. Usually, he's thought to be in his mid-40s to early 50s.
First, you need to understand Deathstroke's character. Know his motives, his skills, and his past. This will help you write him in a way that is true to the original. For example, his mercenary nature and his family issues are important aspects to consider.
Deadpool became Deadpool through a series of complex and sometimes convoluted events in the comics. He was originally a mercenary named Wade Wilson, who underwent experimental treatments that gave him his unique powers and personality.
First, create a unique and believable OC. Give them a distinct personality, backstory, and motivation. For example, if your OC is a former assassin, explain what led them to that path. Second, understand Deathstroke's character. His skills, his code, and his relationships. Then, build a plot that brings your OC and Deathstroke together in an interesting way, like a common enemy or a shared goal.
First, you need to understand the characters well. Naruto is known for his positive attitude, his strong will, and his powerful ninja skills. Deathstroke is a highly skilled assassin with a complex personality. Then, create a unique plot that combines elements from both universes. For example, you could have a situation where the Sharingan (from Naruto) has a strange interaction with Deathstroke's enhanced physical abilities. Also, don't forget about good dialogue. Make it so that the two characters can have interesting conversations that show their differences and similarities.