Birthday: January 5th Shuusei, also part of the guardians, is Hotsuma childhood friend. He helps the police in solving crimes with his "sixth sense". He seems to be a quiet and sensitive person. He carries deep scars on his chest, that seem to be the source of his frail health.
Like Yuki, Shuusei was also a girl in his past life and he was married to Hotsuma.(Source: Wikipedia)