#You need not be your class(es)
You need not be your class(es)
You are playing a character, who has a certain skill set. That character may self-identify as a rogue, and then may recognize a distinct switch from being a rogue to following the way of the monk. Those are options.
They are not the only options. Consider Miko Miyazaki:
Elan: So Miko, did you take levels in the old samurai class or the new one?
Miko: I did not take any levels in any “samurai” class.
Elan: Huh? But you said you were a samurai.
Miko: Yes, that is my position in the heirarchy of my homeland, but it is a social title, not a core class. My class is paladin, not counting the monk training mentioned earlier.
Elan: Ohhhhh, I see.
Elan: So then you took levels in the Master Samurai prestige class.
Miko: No! No, I did not.
Miko: Why is it so difficult to believe that I can be a samurai without having a class with the word “samurai” in the title?? Can there not be facets of life that are not defined solely by class?
She refers to herself as a “samurai,” which confuses the characters in the comic because they think she means her class (it’s a silly comic). In reality, she is a multiclass monk/paladin, “samurai” is her social title and occupation, not her class.
Which highlights my point: it is only a very silly, tongue-in-cheek game (like Order of the Stick itself) where the characters are so deeply familiar with the game mechanics, things like having specific levels. In most games, levels are a metagame construct used to abstract the details of the reality that the characters live in. They are not aware of them.
So a multiclass rogue/monk could be a thief who consciously decided to change things up, joined a monastery or, perhaps in your case, got more disciplined about martial arts training.
Or a multiclass rogue/monk could just be a character who, in-character, was always following a single path – ninja, perhaps – and rogue/monk is just the mechanical way the player has chosen to represent that path.