A
new dungeon can now be accessed in the East of Graal City (towards Master Li's Woods). It is not required to have completed any of the storyline beyond owning a sword in order to begin this quest, though for reasons that shall be learned one can not simply "walk" in to the Mausoleum.
With the release of this quest it is now possible to obtain a 5th heart. It may also be worth looking out for hidden Trading Cards or Gelat chests.