Souichiro Shimoda (下田 宗一郎 Shimoda Sōichirō?), or Takaomi Shimoda (下田 鷹臣 Shimoda Takaomi?), also known as the Gentleman Spirit (謎の紳士 Nazo no Shinshi?, lit. "Mysterious Gentleman"), is a ghost trapped inside Heavenly Host Elementary School. He resides in one of the stalls in the boys' lavatory on the third floor.

Shimoda is, for the most part, a gentleman whose courteous behavior doesn't betray his refined appearance. He is also somewhat eccentric, spouting phrases such as, "I love you!" in English. He claims to have been very protective of his subordinates in life, which carries over in the afterlife as he shows genuine concern for the unfortunate humans trapped inside Heavenly Host.

The only occasion in which he ever breaks this personality is whenever someone opens the door to his residential toilet stall without his permission, to which he furiously roars at the person to shut the door. However, he claims this is so because he is actually easily frightened by his surroundings, and only feels secure inside the stall. Upon meeting him in person, students Nana Ogasawara, Nari Amatoya, and Chihaya Yamase note how friendly he is despite him clearly being a ghost.

When Shimoda was alive, he and his family lived on the land where Heavenly Host Elementary School would eventually be built. He had a lover who died of an illness while waiting for him to return from a voyage overseas. He died of unknown causes at the age of 28. His ghost came to haunt Heavenly Host, residing inside the boys' lavatory on the third floor of the building and rebuking anyone who would open the door to his residential stall, eventually becoming the basis of one of the school's "seven mysteries." He remained trapped in the school after it was demolished and recreated by Sachiko Shinozaki, leaving him unable to pass on to the afterlife.