Koban is a feline journalist specializing in gossip who actively seeks scoops, particularly involving celebrities. After being told by the idol Peach Maki to never go near her, he sets his sights on Hōzuki as a future source of sensational stories.

He becomes involved with Gon, a dropout yakan fox who finds his own transformative abilities bothersome. Koban remarks to Gon, "You're not a fox, you're a tanuki," due to Gon's laziness and dislike of work. An undesirable but inseparable bond exists between them.

In the OVA, Koban appears in a segment titled "The Foxy Yakan and Ooban Koban." He is present in Hell's red-light district when Hōzuki is recruited to train male fox hosts in being sadistic, resulting in Hōzuki becoming mixed up with Koban.

The smoke from Gon's kiseru pipe can take forms reflecting the relationships and state of affairs between those nearby, an ability tied to Gon that is part of Koban's inseparable connection to him.