Kenji Yoshida is the Head Chef of Vinzu, an exclusive sushi restaurant that is a front for contraband trafficking.
Justine learned that Vinzu was a source for high-end contraband, so she decided to send in Ben and Rhys to plant cameras so she could get evidence of illegal activities. She wanted them to go in as exterminators, but Ben and Rhys instead decided to set it up to make it look like Ben was a food critic in order to get Yoshida's attention. While Ben was eating, Kenji came over to his table and asked if he was enjoying his meal. Ben said he could only enjoy it more if Kenji joined him, which he did. Kenji then invited Ben to have dinner the following evening again, along with a private tour.
When they had dinner the next night, Kenji revealed that they secretly served Fugu at the restaurant. As the evening progressed and Kenji got drunker, he revealed that Fugu wasn't the only secret item left off the menu. He wanted to go back home to Osaka because was beholden to investors who forced him to use the restaurant as a front for contraband. He slit open a fish in the kitchen to show Ben it was full of diamonds.
With the knowledge that Kenji wasn't the top of the trade, Ben tried to get more time to get the real masterminds. However, when he went back to the restaurant the next day, he was surprised to learn that Kenji had shut down the restaurant and gone back to Osaka. He left a note for Ben thanking him.
He is a Chef. He had a restaurant, Vinzu, but it was being used as a front for high-end contraband by his investors, so he shut the place down and moved back to Osaka.