She’s basically a little cartoon girl called Marabelle, who was created accidentally because of jokes between Joey and Henry during the cartoon production xD
Marabella isn’t an important character, she’s only on the cartoon for do her “classic” moment, just as many cartoons do, like Skooby doo (in the end always is the same thing, that is, there’s always one person behind everything) This is the “classic moment” of this cartoon
But well, going back to batim, Marabelle is a girl that appears only about ½ minutes per episode, basically, to accidentally destroy something they (others characters) are doing: D And she does not do something REALLY important for the development of the episode. She is a child who LOVES Boris (obviously not romantically) because “he’s a cute dog”, and admires the beauty of Alice
She only disrupts the development of that two characters, in particular Boris. She’s basically a punch line joke on the cartoon for make the watchers laugh.
Curious fact: she doesn’t care about Bendy, she isn’t a fan of him :D I did this because I think Boris deservers a bit of attention