Humans (real life) have been known to take things around them and improve them in their own image. Trees into tree houses, the wood around them into houses, it is no different with fantasy content. We see great things and become inspired we draw upon these inspirations and improve them in our own image. Some of these become legends like Warcraft, some of them forgotten with time or are never great to begin with. It is ok to draw inspiration and make your own story, warcraft is no way a direct copy pasta from one source and that is ok. There is a difference between cloning and drawing from inspiration. Warcraft has drawn from inspiration and is no clone.