Do Rave Master and Fairy Tail share the same world?
The two series are by the same mangaka - Hiro Mashima - so it was this that allowed for the easy crossover OVA, as there were no copyright or licensing discussions that had to be made.

The two series do not share the same world. Rave master takes place primarily in the Continent of Luka, whereas Fairy Tail takes place in Earth Land.

I'm unsure of the overall world name for Rave Master, but there is no Luka in Earth Land and the maps look quite different.



Rave Master World Map



Fairy Tail World Map