Well, in this graphic novel, Deadpool's wacky and unpredictable nature clashes with Thanos' power - hungry and often brooding demeanor. It makes for some really interesting and comical battles.
A possible plotline is that Thanos hears about the powerful chakra in the Naruto world and decides to conquer it. Naruto stands up to him, and during the fight, Naruto unlocks a new form of his power that is on par with Thanos' strength with the Infinity Stones. Along the way, Naruto teams up with some of his old foes who also realize the danger Thanos poses. They all fight together to protect their world.
The plot typically involves the Avengers facing off against Thanos. Thanos usually has some grand plan, like gathering the Infinity Stones to reshape the universe. The Avengers must come together, using their unique powers and teamwork, to stop him from achieving his malevolent goals.
One possible storyline could be that Thanos arrives on Earth seeking a powerful artifact. Superman steps in to stop him. They battle it out across the city, with Superman using his strength and speed to try and take down Thanos. Another could be that Thanos somehow manages to get Superman under his control using the Infinity Stones, and then the rest of the Justice League has to figure out how to free Superman and defeat Thanos.
A Harry Potter who reverses Thanos would be a very interesting concept. Harry could use his ability to communicate with snakes (Parseltongue) to perhaps take control of some of Thanos' minions. His magical items like the Invisibility Cloak would give him an advantage in stealth. He might even use the Time - Turner to go back in time and prevent Thanos from getting the Infinity Stones in the first place. The Hogwarts environment could also be a factor, with its many secrets and magical defenses that could be used against Thanos.
In some fanfictions, there could be a situation where Thanos is actually related to an ancient dark magic in the Harry Potter universe. Harry has to figure out this connection and use it to his advantage. Maybe Thanos is after a powerful magical artifact in the wizarding world that he believes will enhance the power of the Infinity Stones. Harry and his friends then have to protect this artifact while also trying to defeat Thanos, which could lead to a series of epic battles and magical duels.