Minecraft multiverse core WORLD?

Hi! I used the minecraft plugin Multiverse core and wanted to ask:

For example, if I add all the buildings to Die Welt world and then delete multiverse core, will Die Welt world still be there?

As long as you don't delete the world world, it is always there, no matter which Pluin you remove. You could get problems with porting to the world if you don't have a corresponding plugin like erssentials.