Sōjirō Kusaka

was an old friend and rival of Tōshirō Hitsugaya when they were younger in the Shinigami academy in Bleach: The DiamondDust Rebellion. He is the main antagonist in the movie and is a Shinigami which Hitsugaya encounters while searching for the thieves who stole the "King's Seal". He has the same Zanpakutō, Hyōrinmaru, as Hitsugaya.

Appearance
Kusaka is a tall Shinigami with long, black hair tied into a bun at the back. He has red eyes (violet in his academy days) and a large scar running the length of the right side of his face. He wears a light brown cape that is similar to the one worn by Hitsugaya and a mask that resembles a Hollow's mask.

Character Outline
Kusaka started out as an idealist who wished to protect and uphold Soul Society. He met Hitsugaya at the academy. The two were friends and rivals, often competing in school work and practicing together to better themselves. Kusaka's sudden, forced battle with Hitsugaya and subsequent summary execution unbalanced him; after his return he grew bitter and determined to enact revenge upon Soul Society for their arbitrary and harsh codes of conduct.

School Days
During his days in the academy, he was in the same class as Tōshirō Hitsugaya and the two of them quickly became friends. He had regarded Hitsugaya as a genius and strove to be better than him. He also swore his allegiance to Soul Society and worked hard to become a successful Shinigami just to devote his life to them. When Kusaka met his zanpakutō spirit in a cave, he met Hitsugaya there who had also met the same spirit. They were overjoyed to know that both of them had exactly the same powers and their friendship deepened as a result.

First Death
The Central 46 members ruled that two Shinigami cannot hold the same zanpakutō. By the ancient laws of the Shinigami, such a situation was not permissible, although neither Kusaka or Hitsugaya had intended to violate the law. Hitsugaya offered to abandon Hyōrinmaru instead of fighting Kusaka, but the council forced Kusaka and Hitsugaya to fight for the honor of bearing Hyōrinmaru (a possible reference to Gin Ichimaru's earlier comment that Hyōrinmaru marks out a destined hero). It was ultimately Kusaka who drew his sword and charged Hitsugaya, shouting that he wanted Hyōrinmaru for himself. This cost him, as it was never meant to be a dual to the death but a test to see who would raise their blade first.

Before the battle was concluded, the Central 46 members ruled that Hyōrinmaru belonged to Hitsugaya and Kusaka was sentenced to be killed immediately. Though no one had won at the time of the decision, Hitsuguya appeared uninjured, while Kusaka was covered in ice. Numerous special forces members appeared and restrained Hitsugaya while surrounding Kusaka. Several of them stabbed Kusaka in the gut to weaken him before one dealt the fatal blow by slicing open the right half of his face. This is hinted at by his scar, which he somehow retains despite being given a new body.

As Kusaka's zanpakutō dissolved, he asked why he had to die and exclaimed that had fought for Soul Society. His execution was kept secret and his academy records were destroyed afterwards. Almost no one in Soul Society knew of his existence. However, the cover-up was not complete, ultimately enabling Nanao Ise to find a picture of him from his time in Rukongai.

Rebirth
Though the complete process was not shown in the movie, Shigekuni Yamamoto-Genryūsai mentioned that the had given new life and that Hueco Mundo had raised him up, though he was not a hollow. During this time, he gained two loyal arrancar subordinates named Ying and Yang with the powers of fire and electricity. They would help him with his future plans. Returning to Soul Society seeking revenge, he donned a mask and a tattered cape matching that of Hitsugaya's own. He assaulted Shunsui Kyōraku using Hyōrinmaru, leading Soul Society to believe that it was Hitsugaya who did it and labeled him as a traitor. Kusaka then met Hitsugaya again, blaming Momo Hinamori for Hitsugaya becoming a shinigami. He showed him the power of the King's Seal, teleporting both of them to the Sokyōku Hill in Soul Society.

Transformation
Kusaka wanted to use the King's Seal to become the new King of Soul Society. When Hitsugaya refused to use the power of his bankai to cut the King's Seal to release its power, Kusaka remarked that "I can do it myself now" and sliced it into two using his own zanpakutō. He transformed into a purple dragon echoing that of Hyōrinmaru and effectively became a god, regenerating instantly even being cut into two by Kenpachi Zaraki. He became indestructible and wielded immense power, exclaiming that "this power is spectacular". Kusaka "took root" on a tall building, encasing it in ice and merging with it. It evolved into a gigantic tree but he blew it up soon after to stop Shinigami from approaching him. At this point in time, the King's seal went berserk as since Kusaka had not mastered his bankai he could not control the King's Seal's immense power. It created a rapidly expanding hemisphere in which Kusaka created a castle with him immobile atop an ice tower in the center of the castle. The castle spawned numerous Hollow and Menos Grande which all had the same superfast regeneration abilities of Kusaka.

Second Death
After Ichigo destroyed the ice tower and the King's Seal returned to normal, the ice dragon dissolved, revealing Kusaka. Kusaka and Hitsugaya charged at each other for one last time to finish the battle which they had left off. Hitsugaya won and Kusaka told him that his existence will continue, that he would never die, and that they would be friends forever, before dissolving, leaving behind his broken zanpakutō and his cape. Ichigo said that all Kusaka wanted to do was to finish his fight with Hitsugaya.

Zanpakutō
Kusaka has the same Zanpakutō as Hitsugaya,. When sealed, Hyōrinmaru looks just like a normal katana with the exception of the guard, which is shaped like a four-pointed star. The hilt is a deep red. The sheath disappears whenever the sword is drawn.


 * Shikai: Hyōrinmaru's release command is . When released, Hyōrinmaru gains a crescent-shaped blade attached to the base of the hilt by a long chain.


 * Special Abilities: Hyōrinmaru allows Kusaka to control water and ice. His slashes create an immense amount of spirit power which overflows from the tip of the blade, creating a flow of ice shaped like a purple Chinese dragon. The dragon flies at opponents and instantly freezes anything it touches. Kusaka can also direct his slashes towards the ground and form a wave of ice which rushes over his opponents overwhelming and freezing them. The chain-blade freezes anything Kusaka traps within it.


 * Bankai: Not Achieved.

Trivia

 * Despite Sōjirō and Hitsugaya having twin blades, there are several subtle differences between their respective swords. Sōjirō's sword has a dark red hilt and sheath as opposed to Hitsugya's being blue. Also, the guard of Sōjirō's sword is hollow with curved points giving it more of a flower-shaped appearance.