(sigh) Of course they all fall under concepts. Zeus throwing lightning bolts is a concept, that doesn't make it a non-myth. Harry Potter playing quidditch is a concept. The concept of horse is a real concept and the concept of pegasus is a real concept, all concepts are real, there's no such thing as a fictional concept.

Also, I never said the WORD "must" is not real, it's a word. Quidditch is a word, myth is a word and Kryptonian is a word.

EDIT: Sorry for sighing, it's not personal.