Sumiyama Taishi

Takuya's friend from university and also a friend of Satou. He too is coming to the hospital to learn with his friends. He is not stupid but he is not very clever either and he does not get much involved in his academic duties. By cons he is very serious and involved in his work, he is very professional.

When he meets Takuya or Satou, he begins to enter endless conversations with him or her, almost forgetting the rest of the world.