This is my take on One Piece and Marvel. However instead going with the MCU which is more popular and the ones that you all most care, I decided to go with another route: The Ultimate Universe. I mean while is not the best universe that Marvel has produced, it was a really good idea and I love some of the runs. However, I cared mostly for Ultimate Spider Man and a little bit for Ulimate X-men. Seriously I own the Omnibus of Ultimate Spider Man! This is Straw hat after Wano so I will have Jinbei, Carrot and Yamato. So, let's start it.
On the Multiverse
A long time ago a series of Universe were created. A Universe for one reason, a universe for another reason and the list goes on for an eternity.
However, in one example there is a gateway between Universes. Some a more complicated than others, however in some universes they are very simple and easy to access.
In a universe that is named Earth 1610, super heroes would begin to pop out and start be a thing in a few months. However, something else would appear and help those heroes make this very clear.
At the New World.
The straw Hats were sailing after parting ways with their friends at Wano, the crew now completed with their new members Jinbei, Carrot and Yamato was off to find the last Poneglyf and finally find the One Piece. Right now, the crew was just relaxing and sailing away.
''So, you really fought 10 giant gorillas at one point with only a slingshot?" Asked Yamato to Usopp.
''Yes, it was tough but I managed to scare them away. Sure, they were big, but I took care.'' Said Usopp.
''Wow.'' Said Yamato.
''Yes, better write that down Yamato. I want future generations to hear about the great pirate Usopp.'' Said the sniper.
''Of course.'' Said Yamato writing it down.
''Stop with this you liar. Don't put those craps into Yamato books.'' Said Nami hitting Usopp.
''Hey, should I scream when I see an island?" Asked Carrot at the mest.
''No Carrot, we want to stay out for a while. Unless Luffy doesn't stop to bother us.'' Said Zoro.
The crew saw that the next island that they spotted was a big one, it was almost like the size of Onigashima, mostly because it looked like a giant skull. It was so creepy and unsettling, so of course Luffy wanted to go there.
''Wow! This place sounds cool.'' Said Luffy.
''Yes, maybe there is something neat to take it down.'' Said Zoro.
''I feel a great amount of respect for that island.'' Said Robin.
The Straw Hats soon felt that this won't be good, but they need more supplies so it was good to stop for a moment.
''Let's stop there. Let's take some supplies and make sure to stretch our legs.'' Said Luffy.
''Ok captain!'' Scream the crew.
The new island that the crew was about to stop seen nothing much.
However, this island was the gateway for one of the Earths of the Multiverse. The key was a cave that has a warning written on it.
WARNING: Whatever you do not enter here!
Knowing the Straw Hats, it was only a matter of time.