Who invented our World

I note that you categorized your question uner World of Warcraft, so I assume you are referring to that world.

The Warcraft lore states that the origin of the universe is unknown, but the theories surrounding its creation are similar to ours: a great cosmic explosion or an all-powerful entity.
Great and powerful creatures called Titans (an obvious allusion to Greek mythology), who were ruled over by a sect called the Pantheon then proceeded to make the worlds, "They shaped the worlds by raising mighty mountains and dredging out vast seas". The Titans' ultimate goal was to "create order out of chaos".
Meanwhile, the enemies of the Pantheon sought to bring back chaos and devour the energies of the universe in which you play. They reigned supreme in another dimension called the Twisting Nether. The Twisting Nether is a realm of pure chaos and magic, with no sense of space or time. The beings that live within it are considered evil and demonic.

If you want to read a more detailed description, you can find a book called "Mythology of the Titans" at the Scarlet Monastery in Tirisfal Glades.