Yugioh Zexal - The Teenaged Agent (Yu-Gi-Oh Watty Awards 2017)

N has no memories of her childhood or who she is, all she remembers is the letter N, her unique set of skills and dueling. Now at the age of 17, she's in Heartland city, serving Mr. Heartland himself as a secret agent and a number hunter. Because she has no memories she is easily manipulated, so Heartland uses that to control her and keep her under his command, but when a young duelist, a fellow number hunter and a floating blue figure that haunts her dreams come into her life, that command becomes weak and questions start to appear.

Disclaimer: I don't own any of the Yugioh Zexal characters except N.