Driving Force

The Driving Force Love Interest is a love interest that serves as a character's personality change, whether positive or negative.  They can transform villains into heroes and viceversa.

An example for a Driving Force Love Interest is Kagome Higurashi from Inuyasha.  When the series began, Inuyasha was a major jerk to the point he was almost homicidal.  But little by little, she made him a better person.