Yuuto  

Man in Black Mask, Ute, ユート / 黒マスクの男

Yuuto shares an uncanny resemblance to Yuya Sakaki; many people mistake him for Yuya, especially when they first meet. When Yuzu initially encountered him, she believed he was dressed as Yuya. Despite this, Yuuto and Yuya have very similar facial features. Initially, his name was displayed on-screen as "Unknown," and promotional materials referred to him as the Dark Duelist or the Dark Masked Duelist, while characters in the series called him by these names as well.