So the Nexus formed when a cluster of universes grew into each other in an event known as the Great Collision. This caused an overlap, creating a space between the different Universes. So basically the Nexus is one large area in the multiverse that is occupied by several universes, and that kinda messes with how reality works there (this is an excuse for me to do whatever I see fit with everything in my story).
Caption this Meme
