Yuji Sakai

"I'm following this path so I can protect everyone, and so that we can be together. Those are my heart's desires"

- Yuji Sakai to Shana

Yuji Sakai is the main male protagonist of the light novel and anime series Shakugan no Shana, and the false main antagonist of part III. After his mysterious disappearance on the night of Christmas Eve, the night Shana was to confess her love to him, he reappears as the leader of Bal Masque, having merged with their ruler, the Snake of the Festival. Although responsible for a war in which many lives were lost, his ultimate goal is to end the never-ending conflict between the Flame Hazes and the Crimson Denizens and have a happy end with Shana, making him an anti-hero.

He is voiced by Satoshi Hino in the Japanese version of the anime, while in the English version he is voiced by Kristian Ayre in season 1 and Josh Grelle in seasons 2 & 3.

About
In the beginning, Yuji had no villainous traits whatsoever; he was kind, self-sacrificing, compassionate and frequently chewed out Shana for her lack of empathy and borderline nihilism, even being partially responsible for making her a better person. Despite this, he did show a more ruthless at times. This is especially evident in the light novels, where he displays a nihilistic view of the never-ending battle between Flame Hazes and Denizens as early as part I and even attempted to kill Shana's mother figure Wilhelmina Carmel in retaliation for trying to kill him.

Regardless of the adaptation, however, Yuji gradually begins to lose his kind nature overtime, becoming notably colder and starting to treat most people around him with indifference, when previously he had been far more sociable. He seems to lose touch with his humanity, even telling Kazumi Yoshida that he doesn't even consider himself a human being anymore. He also becomes more ruthless, such as when he kills one of the Jaeger Zarovee's duplicates with his bare hands and then proceeds to incinerate the rest.

When Yuji reappears after merging with the Snake of the Festival, he displays a very drastic change in personality and is far more brutal and ruthless in his methods. This is shown in full-force when he causes Margery Daw to have a mental breakdown by revealing that the Silver, the Denizen she had been seeking for much of her life, was nothing but a projection of her emotions, an act viewed as a Moral Event Horizon crossing by many. He also strips Shana of her powers and holds her prisoner in the Palace of Stars, an act he performs after confessing his love for her. Despite this, he states that everything he's doing is so the two o them can be together, describing that as "his heart's desires."

Trivia

 * Satoshi Hino also voiced Ainz Ooal Gown.