Sakura Haruno Weak No More

This story is about Sakura Haruno and her team as she grew up around the age of twelve. Always being ignored and seeing as weak, Sakura leaves Konoha to find power and become stronger. Five years later a mystery shinobi wearing a dark cloak enters the village hidden in the leaves with stealth that is unmatched. Who is this mystery person, and why do they have a certain hatred for the remaining members of team seven?(credited to friends)