Sekijiro Kan

Sekijirou Kan (管赤慈郎), also known by his hero alias Blood Hero "Blood King" (ブラッドヒーロー･ブラドキング) is a Pro Hero and the homeroom teacher of U.A.'s Class 1-B.

Personality
Kan has a caring attitude towards his students. He also views Class 1-A as rivals.

Unforeseen Simulation Joint Arc
Blood King along with the other U.A. teachers arrive at the USJ to help Class 1-A and All Might from the League of Villains' attack.

School Trip Arc
When Blood King and Class B arrived at the Training Camp, Blood King told his class that they had to extend their Quirks and that they should hurry because Class A was already there and that he wanted that his Class got the spotlight for a change. He then explained to his class that Quirks grow stronger as long as they kept on using them. Blood King noted that this training would be done as the students developed over time but they had to do it this way because they did not have the time. He then orders his students to join Class A.

The next day Aizawa went to the facility for supplementary lessons alongside the five students that failed the test and found Blood King who was teaching Neito Monoma there. Aizawa asked him if he could put his students into a study exercise and Blood did not have a problem with that since he had the same idea. Then they are all suddenly contacted by Mandalay through her Quirk and she informed them about the attack of the League of Villains. Eraserhead told Blood to look after the students and stormed out of the building.

After some time, a mysterious figure appears at the entrance of the building and explodes the door, revealing to be Dabi, but Vlad quickly restrains him with his Quirk, and questions him about his goals and allies, Aizawa appears and ends the enemy revealing that he is Just a clone created by the villains and will not reveal anything to them.

One day after the League of Villains' attack on the training camp, Blood King and Shouta are questioned by Naomasa regarding the events that transpired at the training camp.

Hideout Raid Arc
Afterwards, Blood King along with Aizawa and Nedzu appear in U.A.'s public apology broadcast where they apologize to society for their shortcomings. However, society still criticizes U.A. for being unable to protect the students and criticize their security measures for not ensuring the safety of the students.

Shouta tells the reporters that he decided to let the students fight due to not knowing the full situation in order to prevent the worst possible situation from happening and as a result no students were killed (which is the worst possible outcome in his opinion); Nedzu states that the situation would have been much worse if Tetsutetsu and Itsuka did not defeat the gas masked villain. Nedzu also says that they are seeing to the well-being of their students and have not seen any signs of emotional trauma. The reporter asks the principal if U.A. had already failed in securing the students' well-beings due to not checking Katsuki’s mental instability and his “villain-like” performance during the Sports Festival. Blood hopes that Shouta keeps his cool after being riled up by this particular question. Shouta answers that out of all the students, Katsuki was the one who showed that his conviction to be a Hero was the strongest and believes the villains' to be foolish if they think that they can turn Katsuki into a villain. Nedzu backs up Shouta by saying that they are working with the Police Force to investigate Katsuki’s whereabouts and promises to retrieve him.

Quirk and Abilities
Blood Manipulation (操血) After ejecting a certain quantity of blood from the back of his glove, Blood can freely manipulate it. With his Quirk he managed to restrain a clone of Dabi by pinning it to the wall and covering it with the blood, ending the fight in less than three seconds. When he no longer needs it, Blood can reabsorb his blood through the same glove.

Enhanced Strength: Blood is much stronger than the average human. He managed to lift Dabi's clone with a single hand and push it against a wall with enough power to crack it.

Enhanced Speed: Blood King is incredibly fast. He was able to react quick enough to avoid and push the students away from Dabi's surprise attack. He was quick to counterattack against Dabi and had him pinned against the wall in less than three seconds.

Eraserhead
They are both fellow pro heroes and homeroom teachers of the Department of Heroes for their respective classes. As Kan views Class 1-A as his rivals, this rivalry is extended toward Aizawa, with Kan acting out competitively towards him. Despite this rivalry, Kan knows when to cooperate with Aizawa during serious moments.

Toshinori Yagi
While the two have not interacted with one another a lot, Kan respects All Might. He voiced his regret for not acknowledging the large burden that All Might had to shoulder until it was too late

Trivia

 * Blood King's appearance and quirk are similar to Klaus Von Reinherz, a character from Kekkai Sensen.
 * Blood King's haemokinesia may be a nod to the anime Deadman Wonderland.
 * His name contains the kanji 管 (vessel), 赤 (red), 慈 (love).
 * He owns a dog.

Quotes

 * (To his students) "Class A stole the spotlight every time in the first semester, so the second semester's gonna be Class B's time to shine. Got that? Not Class A. Us!"