Emperor Lieutenant Fangore is the co-Emperor of the Silvermoon Empire. When Emperor Hogger is not present to make decisions or is off chasing Hula Girls, Emperor Lieutenant Fangore has the right and duty to act as full leader of the Silvermoon Empire and sit on the really big seat. Nobody is sure exactly how this actually works, but Emperor Hogger declared it to be such.
Emperor Lieutenant Fangore, was crowned as "Emperor of the Second Reign" to replace Emperor Jarethan should the need arise in case of death or abdication or Hogger getting his account hacked. This decision lead to much rejoincing amongst the people of the Riverpaw Empire. Emperor Lieutenant Fangore also corpse-camps the throne just in the off-chance that something happens. Since Emperor Hogger has no consort or children, Emperor Lieutenant Fangore is likely to be the next Emperor of the Silvermoon Empire. He and Emperor Hogger spend a lot of time together, frolicing in the flowers, taking long walks on the beach and sharing tender moments. Read nothing into this at all.
Emperor Lieutenant Fangore is often seen also wearing the same Imperial armor that the Emperor himself wears (probably because they have the same character model) as the are technically both of equal ranking. Though Emperor Hogger is a far more visible sign and symbol of power, Emperor Lieutenant Fangore assists in the runnings of the Empire, with the assistance of the Riverpaw Advisors. It is said that Emperor Lieutenant Fangore is the one behind the power of the Riverpaw Advisors, using them to initiate counter actions against any potentially ambitious Chancellor or High Councilor Mob who would try to usurp power from the Emperor. This is absolutely not becuse he is trying to seize absolute power for himself and merely using them ofr his own ends, no sir. Read nothing into this either.
All up, Emperor Lieutenant Fangore gives the appearnace of being a completely harmless, no-personality sockpuppet of Emperor Hogger himself.