In the guide book there is a comment that Deuce will sometimes make “expressions where you can see the yankee influence”, and Deuce is heavily coded as a former yankee (or maybe just a former aspiring yankee?)
(above: Yana’s memo from the guide book commenting on the “yankee influence” on Deuce)
In his clubwear card artwork Deuce holds his baton in the same way that yankee are often depicted holding pipes for fights in fiction.
For a quick review, The Japanese-language-term “yankee” is for a kind of youth subculture associated with being a rebel and having a tough, flashy appearance, often adopted by teenagers who want to look intimidating, reject societal expectations, be anti-authority, etc.
The term is probably from the American word “yankee” originally, possibly imported with post-war G.I. culture, but it is very much it’s own, independent thing (an example of wasei-eigo (和製英語,) English words that get new meanings after being adopted into Japanese.)
Going in the yankee direction is something that 不良 (furyou) choose to do sometimes, and 不良 are referenced often in Twst, translated on EN as “delinquents” or “young punks,” basically a starting point for kids who will maybe imitate some yankee styles (like Deuce and Epel), get often get into fights, smoke while underage, skip school, etc.
During White Rabbit Fes Epel says he had only heard of 不良-types in comics and TV shows (Idia and Ortho also talk about 不良 of manga, TV shows and movie), and he was shocked to learn that all of it is real. Deuce says, “I know what you mean. I went through a phase like that.”
This was one of the various dichotomies that made the White Rabbit Fes event so fun: Epel goes to Clock Town having heard that it is overrun by 不良, saying he assumed “the town would be awash in modded blastcycles, with 不良 getting into fights all over the place,” and he is disappointed by the reality as he had been “hoping someone would pick a fight with us so l could send them packing.”
Instead, he sells doughnuts while dressed as a bunny.