Mr. Shakedown is a title given to a number of non-playable characters and the centers of many sub-stories in Yakuza 0. Though details vary from person to person, each Mr. Shakedown is generally a large man with an impressive physique who seeks to shake down Kiryu, Majima, and anyone else they can get their hands on to raise funds for various objectives.
Over time, Mr. Shakedown has made a name for himself as Pat's natural predator. The coward Pat tends to flee at the very sight of Mr. Shakedown unless he is stocked with health- and heat-restoring items, and even in such cases the sheer power of Mr. Shakedown's attacks often have the ginger on his knees and penniless before he can even take a sippy of his
estus flask Staminan Royale. Over time Pat has gotten some good hits in and learned more effective cowardly tactics for dealing with Mr. Shakedown, but the score still remains in Mr. Shakedown's favor.
One particular Mr. Shakedown aspires to become the ultimate fighter on the planet, "standing on the apex of all organisms", much like Randy Orton. This quest requires a large sum of financing to achieve. Since Sky Finance hasn't yet been founded, Mr. Shakedown's alternative plan is to shake down people who step on his turf for money, including Kiryu Kazama himself. Matt occasionally refers to this Mr. Shakedown as "Dr. Shakedown," implying that the incredible amounts of money he has stolen from Pat over the playthrough allowed him to attend and graduate medical school in record time. He presumably uses his newfound medical expertiese to patch up his victims so that he may shake them down even harder next time.
Another Mr. Shakedown prowls the streets of Sotenbori, shaking down wealthy men like Goro Majima and using any stolen money to enjoy himself at various venues. This particular Mr. Shakedown is not as intimidating as the one Kiryu first runs into in Kamurocho, but has proven to be just as capable when it comes to shaking down cowards like Pat.
Mr. Shakedown's deeds are not limited to Japan. He has also been sighted in Gotham City, beating down the GCPD and bank tellers while absorbing their money and investing it on himself "literally".