Complex sentence: Quidditch has its roots in the fictional Harry Potter sport of the same name, however to denote the difference, the fictional sport uses the capitalised "Quidditch" whereas the sport played as per the IQA rules uses the uncapitalised "quidditch".
Split into simpler sentences: Quidditch has its roots in the fictional Harry Potter sport of the same name. To denote the difference, the fictional sport uses the capitalised "Quidditch" whereas the sport played as per the IQA rules uses the uncapitalised "quidditch".