Konosuke Yowai

Psychiatrist, said to be very intelligent with an outstanding medical career, including a stay at Harvard. Calm and cheerful in his demeanor, seeming like an airhead. His family name is phonetically identical to the word for "weak", and his given name can be read as "saving happiness".

It is hinted at the end of the first chapter that the loss of a loved one motivated him to pursue a career in mental health.