According to the rumor, if a Devil Fruit user went near an uneaten Devil Fruit, a devil would come out of the fruit and rip the user apart. However, most critics recommend the book as a great learning tool for students who already hold some background mathematical knowledge, or for younger children who could read it with a more experienced adult’s guidance.

The seventh night brings Robert to a bare, white room, where the Number Devil presents Pascal's triangle and the patterns that the triangular array displays.A digitalised version of Enzensberger’s book with all mathematical explanations and illustrations can be found here.

Additionally, since each Devil Fruit user possesses a unique ability, they each require different countermeasures to deal with them, outside of the standard Devil Fruit weaknesses of Seastone and the inability to swim.

This gives them the mobility, abilities, and intelligence of the animal they turn into, in addition to having the properties and abilities of the object they were made from. However, if the user's body has been permanently altered by the fruit, then the user's ability can be manipulated by outside sources; e. while trying to dial either 666-666-6666 or 1-666-666-66666 you'll be able to handiest superstitiously consider that the devil may be dialed. Another similarly problematic theory identifies 666 as Muhammed, the founding Islamic prophet viewed as a false prophet in medieval Christianity.