A underground doctor who lives with Celty and is her self-proclaimed boyfriend.
When Shinra was just 5 years old and his father was a well-renowned doctor, he discovered Celty hiding in the cargo hold while exploring the cruise ship he was on. When Shinra's dad convinced Celty to let him examine her, he offered to let his five-year-old son briefly experiment his medical skills on her as well. For some reason, it was through this act that he not only decided to become a doctor, but also to fall in love with Celty.
At some point during his teenage years, Shinra shared a room with Shizuo and Izaya when they went to the same high school, as well as Celty who was doing retrieval jobs for money on the side. Even after they drifted apart, Celty continues to be his roommate, but Shinra constantly tries to convince her to fall in love with him and become his wife, swearing that she looks perfectly fine even without her real head.
In the present, Shinra is a skilled doctor who often works off the books for people who don't want to be identified, whether that involves doing a job for Yagiri Pharmaceuticals or someone from the yakuza needs a bullet taken out of their body. He rarely gets angry or agitated unless he thinks Celty might be in trouble.
It's strongly hinted that Shinra might know where Celty's head is now, but he will not reveal it because he's afraid that if Celty regains her identity and memories she will no longer be the same person he currently loves.