As a group of many many characters all interacting with each other while also trying to get back to their own universes and helping the people of the Neon Genesis universe defeat the angels. 

All anime characters all stranded in a new place.

By role playing as characters from mythology, fiction, and religion. 

Reality is breaking you have to fix it. 

Note your effect will change the story of the original marineford like you could train luffy or get a wanted poster but either way no one will mess with you after the war not even the yonko and admirals

A devastating war that change the world

They are a group of people working hard to fight pirates and revolutionary army the most notable members are the Admirals which each have there own sense of morality and different personalities. 