|Kosaka is STNJ's office chief. He's a funny guy and is always presented to bring in comedy effects to the series. |
Kosaka has a crazy temper and is always yelling and screaming at the STNJ members. He tends to respect Amon but is very picky toward Doujima.
Although he appears quite "weak" and "userless" in most of the episodes, the chief accomplishes a big role near the end of the series by helping out Amon and Robin.