Seiryu

Seiryu is arrogant, ruthless and contemptuous of those he considers weak. He shows little concern even for allies once they have ceased to be useful.

His cruelty particularly angers Hiei, who has little patience for a fighter who treats his own comrades as disposable. Seiryu's confidence in his speed and ice techniques makes him assume he can dictate the pace of their battle.

He is more composed than Byakko but possesses a similarly inflated sense of superiority.

Seiryu manipulates demonic energy as extreme cold, allowing him to freeze targets and the surrounding environment. His signature attacks can release numerous rapid ice strikes within moments.

He is also extremely fast. In the anime, his exchange with Hiei occurs at speeds difficult for ordinary observers to follow, forcing Hiei to match him with equally rapid movement.

Seiryu is generally identified as a middle C-Class demon. Although dangerous at this stage of the series, his power is far below the levels Hiei later reaches.

Seiryu is the third Saint Beast standing between Yusuke's group and Suzaku. His confrontation follows the battles against Genbu and Byakko.

When the weakened Byakko reaches Seiryu, Seiryu freezes and destroys his own ally rather than helping him. The act immediately establishes the contempt he has for weakness and provokes Hiei.

The manga resolves their confrontation extremely quickly, with Hiei's speed overwhelming Seiryu almost before he can respond. The anime substantially expands the battle, allowing Seiryu to demonstrate more of his ice techniques before Hiei surpasses him.

Hiei is Seiryu's opponent at Maze Castle and reacts with disgust to his treatment of an injured ally.

Byakko is Seiryu's fellow Saint Beast, whom Seiryu mercilessly attacks after Byakko returns defeated.

Suzaku leads the Four Saint Beasts.

Genbu is another member of the Four Saint Beasts.

Yusuke Urameshi, Kazuma Kuwabara and Kurama accompany Hiei through Maze Castle.