Hobby: Collecting teacups
Tsugumi Ohba is a fictional writer credited with writing the manga Death Note. Their real identity (and gender) is a closely guarded secret. Some fans believe that Tsugumi Ohba is just a pen-name for Hiroshi Gamou.
Day and night, develops manga plots while holding knees on a chair (reminiscent of one of the main characters in Death Note, L.)
(Source: The VIZ English graphic novel's profile)