The Fifth Marauder
Part I: She is a shame to her family. Annali (Annie) Lestrange is the invisible Lestrange that no one knows exists. When she goes to Hogwarts, she expects the same. Her older sister, Bellatrix is a fifth year, five years older than she. But she doesn't begin on the path anyone in her family did. She's delighted to find she's joining her favorite cousin, Sirius Black, in school. But as the events unfold, she is disowned from the Lestrange family. This part follows her through her years at Hogwarts with her best friends, the marauders, and her other two friends, Lily Evans and Severus Snape.
Part II: Two of them are dead. Her best friend in the entire world, James Potter, is gone. Annie doesn't even have to think when Dumbledore asks her to return to Hogwarts as the head of security in Harry's second year. She also becomes a teacher assistant when needed in all classrooms. This book follows her through Harry's years at Hogwarts.
DISCLAIMER: I DO NOT OWN HARRY POTTER. ALL CREDIT EXCEPT FOR ANNIE GOES TO THE WONDERFUL MS. J.K. ROWLING, GODDESS OF EVERYTHING.