Whether in the East or the West, 7 is considered a very magical number.
God created man in 6 days and rested on the 7th day. There are 7 sins in mankind. There are 7 seals in the Book of Revelation in the Bible. The list goes on and on.
The "Heptagram" has seven corners, and each vertex means an element. This story is also composed of seven short stories.
Cape of the Wind - the heroine Astoria Greengrass, the hero Draco Malfoy.
The Horn of Fire - the male protagonist Sirius Black, the female protagonist is the original.
Water Point - the heroine Hermione Granger, the male protagonist is the original.
Dirt Horn - The male protagonist Blaise Zabini and the female protagonist Pansy Parkinson.
Corner of Light - The male protagonist is Harry Potter, and the female protagonist is original.
The Dark Corner - the male protagonist Tom Riddle, the female protagonist is the original.
The Hollow - the heroine Narcissa Black, the hero Lucius Malfoy.