Kotori Mizuki

Kotori is a very cheerful girl with the ability to manipulate computers. She is protective and fiercely loyal to Yuuma, as she admires his unwavering will and determination of constantly challenging himself. Despite the fact that Kotori sometimes gets annoyed by Yuma's naivety and childish outbursts, she appears to harbor a deep crush on him.

(Source: Yu-Gi-Oh Wikia)