While they are called “Fivers” because they accept the first four Imams recognized by Twelvers and Isma‘ilis (“Seveners”) and recognize Zayd ibn ‘Ali as the rightful successor to his father ‘Ali Zayn al-‘Abidin while other groups recognize his brother Muhammad al-Baqir, they do not then insist that all rightful imams must descend from Zayd.