I'm pretty sure you were dreaming. Hero and Legendary ranks are semi-permanent (usually permanent but can be reverted if an admin sees), and at least usually last for a month.
Your enthusiasm intrigues me. You have dreams of earning a blue half-coin? :-/
I think admin can demote any rank why you say Here and Legendary is semi-permanent? Same applies to each and every rank I guess.BTW who wouldn't be enthusiastic about being a Legendary?