He returned because he realized he cannot live without her.
Taylor Lautner plays Jacob in the Twilight film series.
Carlisle Cullen (also known as Stregone Benefico) is Esme Cullen's husband and the adoptive father of Edward, Emmett and Alice Cullen, as well as Rosalie and Jasper Hale.
Carlisle theorizes that when a human is turned into a vampire, they will have an enhanced ability from their previous life.
He believes he brought compassion from his human life.
Knowing he would be rejected by society, he hid himself and silently endured the painful transformation, emerging as a vampire.
Horrified by what he had become, he attempted suicide multiple times, but failed due to his supernatural strength.
Kristen Stewart plays Bella in the Twilight film series.
Edward Cullen (born Edward Anthony Masen) is a major character, implicated in all of the Twilight Saga films and books.
Bella expresses a desire to become a vampire herself, against Edward's wishes.
In the second novel, New Moon, Edward and the other Cullens leave Forks in an effort to keep Bella safe from the vampire world.
Carlisle has had centuries to perfect his medicinal talents, therefore making him an excellent doctor.