Maka Adone

An orphan who joined a paladin order along with her best friend Calliope, before they were separated as Calliope went missing on a mission. She went out looking for her and has been doing so ever since, never quite being able to find her. Her Oath was never quite the same as the others, born instead from her love and devotion to her friends and allies, allowing her to transform.

She also has a MotW variation that is a human with a similar concept and backstory.