Teitou High School (帝東高等学校 Teitō Kōtō Gakkō) is located in East Tokyo and is an escaltor school with a junior high division Teitou Junior High (帝東中学校 Teitō Chūgakkō). It's baseball team is known as "The Invincible Legion" due to having reached Koshien 21 times in their history, they have also been Koshien champions on two occasions. Their team's defense holds the title of "The Iron Wall". The team is coached by Okamoto Ippachi.
Teitou won the East Tokyo Regional Tournament to qualify for the 89th Summer Koshien, and made it to the best 16 led by their first year ace Mukai Taiyou.
After their long off-season, they have reached the semifinals of the Spring Tokyo Metropolitan Tournament. They defeated Fall Tournament semifinalists Seiko Academy in the fourth round and Ugumori High in the quarterfinals. They lost however to their fellow Summer Koshien participants from last year, Inashiro Industrial in the semifinals. They will be a seeded team in the East Tokyo Regional Tournament qualifier for the 90th Summer Koshien.