Nothing is known about Shuuhei’s zanpakutou. It appears that when he was winning against Yumichika, he didn’t even bother releasing it. However, he was taken by surprise by Yumichika’s shikai, and defeated before he had a chance to do anything.
Hisagi Shuuhei served as vice captain to Tousen Kaname in the Ninth Division. Since Tousen’s betrayal with Aizen, the current status of the Ninth Division’s captainship is unknown, so it could be assumed that Shuuhei is acting captain until a new captain is chosen.
Shuuhei has short, dark hair and wears sleeveless shinigami robes, and has the number 69 tattooed to his left cheek and has a set of three scars straight over his eye and down his right cheek. He also has a blue, stripe tattoo running across his left cheek and over the bridge of his nose over the 69. He wears what appears to be a jeweled choker around his throat, and a matching armband on his right arm. He has his vice captain insignia tied to his left arm.
Hisagi Shuuhei was a famous shinigami even before he was officially a shinigami. In the omake chapter directly preceding chapter 173, we learn from Kira Izuru that Shuuhei was already taking missions from the Gotei 13 even though he was still a student of the Shinigami Academy. In that same chapter, Shuuhei is assigned, along with two of his classmates, to lead a field lesson on performing the konso with Freshman Class One, Kira, Renji, and Hinamori’s class. All went well until the end of the lesson, when the class was taken by surprise by a group of giant hollows.
Both of Shuuhei’s classmates are killed, and he orders all the freshmen to run as he tries to hold off the hollows until help arrives. However, he is quickly overpowered, and if Hinamori, Kira, and Renji hadn’t turned back, Shuuhei would have died then and there. Backup arrives in the form of Captain Aizen and his then Vice Captain Ichimaru Gin. The scars on Shuuhei’s face were acquired in that incident.
Before Rukia’s execution, Shuuhei accompanies his captain Tousen and the captain and vice captain of the Seventh Division, Komamura Sajin and Iba Tetsuzaemon, to confront Captain Zaraki Kenpachi of the Eleventh Division because Kenpachi is assisting the ryoka. Though Kenpachi claims that he can take on all four and assumes the others have gone ahead. However, he is surprised to discover his third and fifth seat officers have remained behind to challenge the two vice captains. Kenpachi grants permission for Madarame Ikkaku and Ayasegawa Yumichika to fight Iba and Shuuhei. They lead their opponents away from the captains in order to avoid getting in the way. Ikkaku takes Iba and Yumichika takes Shuuhei.
In the beginning of the fight, Shuuhei is winning, and chides Yumichika for thinking a fifth seat shinigami could defeat a vice captain. However, Yumichika turns the tables by releasing his zanpakutou, which, until that point, was all but unknown. The next time we see Shuuhei, he’s collapsed in exhaustion and disbelief. To quote him directly: “I didn’t know a zanpakutou like that even existed...” Yumichika rejoins Kenpachi after his captain is done battling, and he looks more full of energy than when he began.
Shuuhei is devastated by the news that Tousen is a traitor to Soul Society. In the aftermath of Aizen’s retreat into Hueco Mundo he visits the grave of Tousen’s friend, and encounters Komamura, one of Tousen’s best friends. They swear to each other that they will save Tousen from himself and his crazed sense of justice.
After that the Tenth Division Vice Captain Matsumoto Rangiku sees him and invites him to drink with her and Kira, who is already passed out. Shuuhei accepts the invitation only to find that Kira needs some serious attention and Rangiku is just ignoring him so she can keep drinking.
From the few other times we’ve seen Shuuhei, he’s generally been in the company of Kira or Renji. He apparently comes from the lower class, but when he’s pressed for cash, he’ll rely on any free food source available, including one provided by someone as obtuse and snotty as the vice captain of the Second Division, Oomaeda Marechiyo. He’s also just as perverted as the other male shinigami, and has a crush on Matsumoto.
Shuuhei is a loyal shinigami whose ideals have been thrown for a minor loop by the betrayal of his captain. He is currently still in Seireitei, and it is yet unknown whether or not he’ll show up on Earth with Renji, Matsumoto, Hitsugaya, Ikkaku, and Yumichika. However, it is a sure thing that we’ll see him again sooner or later, because of his vow to save Tousen.