Ginny was the one who did it all. She was controlled by Tom marvolo riddle, aka voldemort.
Harry sets Dobby free with a sock.
Lucius Malfoy gave the tom riddle diary to Ginny Weasley
There is a cursed child in it (Draco)
The Chamber of Secrets is Opened
Hermione gives birth at 12 in the middle of the plot, rendering her unable to contribute in battle