you were a Monokub. But you were different than Monokuma, Monotaro, Monophanie, Monodam, Monosuke and Monokid. You were...nicer. that's why you weren't allowed to interact with the students.

but one day, Kokichi, Miu and Keebo found you and took you with them. They were like parents with you. And they present you to the others student.

Keebo : but...wouldn't you guys wanted a monokub as an ally for once ?

Miu : yeah and plus, look at them ! They so cute

nobody was convainced...