Deuce is big on hierarchy, never referring to any upperclassmen character by anything except last-name-senpai (except Jamil in a special, one-time exception), and this is also possibly a holdover from his 不良 days.
This seems to be difficult to portray about Deuce in English, so to compensate the official translation of the first novel added the line “Are you trying to overturn the natural order of upperclassmen and lowerclassmen?!” to Deuce’s dialogue so that English speakers are able to understand this about his character, even though that is something that Deuce has canonically never said in any retelling of Twst.
We also see this during White Rabbit Fes where Deuce insists on Silver having the first bite of a shared potato and leading the group in a cheer, as Silver was the most senior of the group.
During the Rapunzel event Deuce insists on fixing Riddle’s hair for him after Riddle’s cuts it himself with magic, saying, “I can’t let my boss be seen looking improper. I gotta uphold our dorm’s rep!”
While doing his best to put distance between himself now and the self of his 不良 days Deuce will sometimes slide back into his old speech patterns and violent tendencies, commented on by characters such as Grim, mobs and Ortho as Deuce becoming a different person.