Alison Is the Ring leader of a group of friends Aria, Emily, Hanna, and Spencer. She was Killed Mysteriously but later found out that the girls were friends with Courtney Ali's Twin.
Ali is the Popular girl lots of people admired her or wanted to kill her. In the books many people were thought to have killed her but they find out later who did.
Alison is discribed as Mean, Beautiful, Popular, Insane and ect.