Board Thread:General Discussion/@comment-153.31.112.21-20180815132541/@comment-32442141-20181019194727

I've always assumed the numbers were given randomly to the original twelve members of the Troupe by Chrollo when the Spider formed. It can't be based on months as Nobunga and Hisoka's birthdays are known and neither correspond to their numbers for day or month. Also if it is based on birthday then what happens when a new member joins as they most likely wouldn't have been born on the month for the number they are replacing.