Yami Shay

Yami Shay,(闇のシェイ Dark Shei), is the spirit of Commander Beset, who had been sealed within the Millenium Chain by the Distinct Enchanter before her death.

After Shay had repaired the Millenium Chain, Yami Shay at first, took over Shay completely, making Shay being able to voluntarily transform impossible. Her situation was similar to the spirit of the Millenium Ring and Bakura. The Millenium Gage also was stuck to Shay because of Yami Shay's fear of losing her host's body.

Before dueling Yugi, she was shocked to see the Millenium Puzzle around his neck and challenged him to a duel. After dueling the Spirit of the Millenium Puzzle(Yami Yugi), she had a flashback about her past, but stated that she had no memory of who she is and had been frantically searching for answers through dueling random strangers.

Personality
Yami Shay is recognized as a rather childish yet forceful person intact with guts and a heart for strong friendships and bonds between a person. She is also alert and spontaneous from her past life.

Yami Shay knows perfectly well how to the game Duel Monsters is played and possesses the same consideration of Dueling as a game of survival. Like Yami Yugi, she believes in the Heart of the Cards, generally on her Distinct Enchanter and Cryptic Wyvern, whom she feels she has an unusual strong connection with.

Yami Shay, at first, did not trust her host's body, therefore making the Millenium Gage bond to her right hand to ensure she will not lose her body. After Shay had proven that she would not abandon her, Shay was voluntarily able to remove the Gage when necessary.

Aside from Yami Shay's intent personality, she adores fooling around with the weaker Duelists and mocking Joey, Tristan, and Duke when they are all with Serenity. She had shown to be quite childish during Duelist Kingdom when Shay allowed her to push their opponent off the cliff into the water after they defeated him for his star chips.

Design
Yami Shay's appearance is vastly similar to Shay herself, but has distinct features to separate her from Shay's appearance. The major difference is Yami Shay's aggressive side and strength. Both her aggressive side and strength can occasionally get out of hand, forcing Shay to switch out before Yami Shay could cause severe damage.

Yami Shay has waistlength hair that is a darker shade of blue (almost black). Her hairline is also different from Shay's. Her eyes appear to be solid black and narrow with an intense gaze. Her hair notably flows and shines beyond Shay's hair.

At the start of the anime, she is seen wearing the standard male Domino High uniform and has a string wrapped around the strand of hair in between her hairline. During the Duelist Kingdom arc, she wore a gray shirt, white knee-high shorts, and deep blue boots.

When watching Yami Yugi and Joey play Dungeon Dice Monsters against Duke Devlin, she's seen wearing her hair in a ponytail with one strand hanging, a light green tank top, a white wrist warmer on her left wrist, black jeans, and blue Toms.

During the Battle City and Virtual World arc, she wore a simple white half-long shirt with a light blue scarf around her neck. A pair of gray jeans and black Velcro shoes complete the look.

During the Waking of the Dragons arc, she wore a black and white jocky shirt, blue shorts, and black sneakers. Since Shay is her host body, her arm was assumed to be dislocated as well.

During the Capsule Monster series, she had only been seen in her school uniform.