Ace's new disguise's name was Adolph, and he was part of the guard force of this servant mountain which was usually called Servant Mountain City.
As the name suggests, the Servant Mountain City was a specific city for only Servant Rank members of the Sun and Moon Sword Union.
The Mortal Domain followed a special law of the Union, and people were divided into four ranks. The lowest rank was Union Servant, then Union Citizen, Union Officer, and Finally, Official Union Member.
The people of the servant rank wore white color clothes, and they did odd jobs in Mortal Domains issued by citizens and earned Union Merits by doing those jobs.
The Union Merits were the currency of the Union, and they can be used in various ways. One of the most common and important uses of Union Merits was it could evaluate someone's status rank in the Union.
A Union Servant can become a Union Citizen as long as he has enough merits.