Kohana Takashi is the consulate general of Japan.
After Kenji escaped, Rhys and Ben used the cameras Rhys had placed to find the person who came to collect the diamonds. Unfortunately, Justine noticed that she had a diplomatic pouch with her. They figured out the woman worked for Kohana Takashi, the Japanese Counsel General, but the FBI decided not to pursue the lead because they didn't want to create an international incident. Rhys and Ben then suggested they investigate and then once they had what they needed, they could leak enough information to the press to force an arrest, getting the arrest without creating an incident. Their way in was through Kohana's son, Jesse, who is into all things high-end. They planned an exclusive dinner party and then invited all Jesse's friends, to make him desperate to attend. Once Jesse figured out all his friends had been invited, he came to Rhys directly to ask for an invitation.
At the party, Rhys charmed Kohana as she drank. At the end of the evening, Ben served her fugu to give her a taste of what they could offer. Rhys let her know that their suppliers could get whatever they needed. Jesse stepped in and, seeing that his mom was drunk, said he was going to call a car to take her back to the consulate. ("The Dining Hall")
While Justine was driving her home, Kohana confessed to every indescretion and then kiss Justine and threw up on her. After her son was extradited, she went to rehab for alcoholism. ("The Family Way")
She was married until her husband died. ("The Dining Hall")
She flirted heavily with Rhys while they socialized at the dinner party. ("The Dining Hall")
She kissed Justine when Justine drove her home. ("The Dining Hall")
The only thing she cares more about than her job is her son, Jesse. ("The Dining Hall")
She is the consulate general of Japan. ("The Dining Hall")