O is for orphan, the central character of children's literature. Like almost everything in children’s literature, orphans can be traced back to myths and folktales, in which the symbolic removal of parental figures is the foremost requirement for a successful rite of passage. A children's literature child is an orphan by definition, whether actual or symbolic. As long as the child is under parental protection, nothing interesting can happen. So the first duty of a children's literature parent is to be absent, preferably dead, but temporary absent will do. Even just emotionally absent will do.
If you browse mentally through children's books you know, all characters are orphaned in some way or other. A socio-historical scholar would say that the abundance of orphans in early children's literature reflected mortality rates in society, and I would ask: so why are there still so many orphans in children's books today, disproportionally many? Because, says my non-mimetic critical self, literature is not a direct reflection of reality, but a distorting mirror.
O is also for omission, which is one of the most fascinating narrative devices. Omission of parents must have a very good reason. Did the little prince ever have a mum and a dad?