Leadership.

There are 9 Leaders who have been chosen by their respective Brothers.

The current theory is that the Leaders were chosen due to their qualities and these qualities' relations to their Group Numbers.

For example, the numerological qualities of the number 4 are:

"You are practical, detail-oriented, organized, orderly, systematic, methodical, precise, reliable, punctual, dependable, honest, trustworthy, without artifice."

And Leader IV has said that these qualities apply to him. So far, five other Leaders have confirmed the links between the numerological qualities of their number and their personality.

The former Leader VII has said they do not match, but the new leader VII says it's fairly accurate for her.