Great Gatsby- What was Myrtles purpose in the book?

shes the one that caused most controversy. she was the one tom had an affair with, and the one that daisy accidentally killed by hiting her with gatsby's car. since it technically was gatsby's car that killed her, myrtle's husband umed that gatsby was the one who killed her, so to seek vengance he murdered gatsby. it all traced back to myrtle, if myrtle was never involved with tom, gatsby would never have died.