Genuine answer? The Kickstarter had a donation level where people could visit Yacht Club Games as a "Director for a Day" and oversee the creation of a character. All four "bonus fighters", as well as those purple Tower samurai, came from donators who won that honor. While The Baz is an existing character and the donators were from the Best Friends Zaibatsu, the other three are original creations.

...though, interestingly, Reize Seatlan is apparently an OC of a German online artist who has also appeared in such games as Endica VII and Valdis Story.

It was a joke. But thanks for the trivia for people who don't know that!